SEC Info℠  
    Home      Search      My Interests      Help      Sign In      Please Sign In

Mednax, Inc. – ‘10-K’ for 12/31/20 – ‘EX-101.DEF’

On:  Thursday, 2/18/21, at 7:00am ET   ·   For:  12/31/20   ·   Accession #:  1193125-21-47064   ·   File #:  1-12111

Previous ‘10-K’:  ‘10-K/A’ on 4/28/20 for 12/31/19   ·   Next:  ‘10-K’ on 2/17/22 for 12/31/21   ·   Latest:  ‘10-K’ on 2/20/24 for 12/31/23   ·   28 References:   

Find Words in Filings emoji
 		  in    Show  and   ↓Hints

  As Of               Filer                 Filing    For·On·As Docs:Size             Issuer                      Filing Agent

 2/18/21  Mednax, Inc.                      10-K       12/31/20   96:10M                                    Donnelley … Solutions/FA

Annual Report   —   Form 10-K
Filing Table of Contents

Document/Exhibit                   Description                      Pages   Size 

 1: 10-K        Annual Report                                       HTML   1.49M 
 2: EX-10.21    Material Contract                                   HTML    111K 
 3: EX-21.1     Subsidiaries List                                   HTML     28K 
 4: EX-23.1     Consent of Expert or Counsel                        HTML     26K 
 5: EX-31.1     Certification -- §302 - SOA'02                      HTML     33K 
 6: EX-31.2     Certification -- §302 - SOA'02                      HTML     33K 
 7: EX-32       Certification -- §906 - SOA'02                      HTML     28K 
14: R1          Cover Page                                          HTML     89K 
15: R2          Consolidated Balance Sheets                         HTML    148K 
16: R3          Consolidated Balance Sheets (Parenthetical)         HTML     42K 
17: R4          Consolidated Statements of Income                   HTML    143K 
18: R5          Consolidated Statements of Equity                   HTML     96K 
19: R6          Consolidated Statements of Cash Flows               HTML    151K 
20: R7          General                                             HTML     32K 
21: R8          Coronavirus Pandemic ("Covid-19")                   HTML     41K 
22: R9          Summary of Significant Accounting Policies          HTML     92K 
23: R10         Investments                                         HTML     40K 
24: R11         Accounts Receivable and Net Revenue                 HTML     61K 
25: R12         Property and Equipment                              HTML     41K 
26: R13         Business Combinations                               HTML     32K 
27: R14         Goodwill and Intangible Assets                      HTML     54K 
28: R15         Discontinued Operations                             HTML     42K 
29: R16         Accounts Payable and Accrued Expenses               HTML     41K 
30: R17         Operating Leases                                    HTML     67K 
31: R18         Accrued Professional Liabilities                    HTML     55K 
32: R19         Line of Credit, Long-Term Debt and Finance Lease    HTML     69K 
                Obligations                                                      
33: R20         Income Taxes                                        HTML    115K 
34: R21         Common and Common Equivalent Shares                 HTML     44K 
35: R22         Stock Incentive Plans and Stock Purchase Plans      HTML     66K 
36: R23         Common Stock Repurchase Programs                    HTML     33K 
37: R24         Retirement Plans                                    HTML     35K 
38: R25         Commitments and Contingencies                       HTML     34K 
39: R26         Selected Quarterly Financial Information            HTML    196K 
40: R27         Summary of Significant Accounting Policies          HTML    115K 
                (Policies)                                                       
41: R28         Summary of Significant Accounting Policies          HTML     61K 
                (Tables)                                                         
42: R29         Investments (Tables)                                HTML     39K 
43: R30         Accounts Receivable and Net Revenue (Tables)        HTML     63K 
44: R31         Property and Equipment (Tables)                     HTML     40K 
45: R32         Goodwill and Intangible Assets (Tables)             HTML     53K 
46: R33         Accounts Payable and Accrued Expenses (Tables)      HTML     40K 
47: R34         Operating Leases (Tables)                           HTML     70K 
48: R35         Accrued Professional Liabilities (Tables)           HTML     51K 
49: R36         Line of Credit, Long-Term Debt and Finance Lease    HTML     61K 
                Obligations (Tables)                                             
50: R37         Income Taxes (Tables)                               HTML    114K 
51: R38         Common and Common Equivalent Shares (Tables)        HTML     43K 
52: R39         Stock Incentive Plans and Stock Purchase Plans      HTML     60K 
                (Tables)                                                         
53: R40         Selected Quarterly Financial Information (Tables)   HTML    194K 
54: R41         Coronavirus Pandemic ("COVID-19") - Additional      HTML     69K 
                Information (Detail)                                             
55: R42         Summary of Significant Accounting Policies -        HTML     70K 
                Additional Information (Detail)                                  
56: R43         Summary of Significant Accounting Policies -        HTML     40K 
                Schedule of Net Revenue by Service Line (Detail)                 
57: R44         Summary of Significant Accounting Policies -        HTML     37K 
                Schedule of fair value on a recurring basis                      
                (Detail)                                                         
58: R45         Summary of Significant Accounting Policies -        HTML     38K 
                Schedule of financial instruments that are not                   
                carried at fair value (Detail)                                   
59: R46         Investments - Schedule of Investments (Detail)      HTML     40K 
60: R47         Accounts Receivable and Net Revenue - Schedule of   HTML     35K 
                Accounts Receivable, Net (Detail)                                
61: R48         Accounts Receivable and Net Revenue - Schedule of   HTML     43K 
                Net Revenue (Detail)                                             
62: R49         Accounts Receivable and Net Revenue - Schedule of   HTML     39K 
                Net Patient Service Revenue by Type of Payor                     
                (Detail)                                                         
63: R50         Property Plant and Equipment - Schedule of          HTML     42K 
                Property and Equipment (Detail)                                  
64: R51         Property and Equipment - Additional Information     HTML     30K 
                (Detail)                                                         
65: R52         Business Combinations - Additional Information      HTML     58K 
                (Detail)                                                         
66: R53         Goodwill and Intangible Assets - Additional         HTML     35K 
                Information (Detail)                                             
67: R54         Goodwill and Intangible Assets - Summary of         HTML     40K 
                Intangible Assets, Net (Detail)                                  
68: R55         Goodwill and Intangible Assets - Amortization       HTML     39K 
                Expenses for Existing Intangible Assets for the                  
                Next Five Years (Detail)                                         
69: R56         Discontinued Operations - Additional Information    HTML     96K 
                (Detail)                                                         
70: R57         Accounts Payable and Accrued Expenses - Schedule    HTML     43K 
                of Accounts Payable and Accrued Expenses (Detail)                
71: R58         Operating Leases - Schedule of operating            HTML     42K 
                lease-related right-of-use assets and related                    
                liabilities recorded on the Company's balance                    
                sheet and the weighted average remaining lease                   
                term and discount rate (Details)                                 
72: R59         Operating Leases - Schedule of lease costs for      HTML     36K 
                operating leases (Details)                                       
73: R60         Operating Leases - Schedule of supplemental cash    HTML     28K 
                flow information related to operating leases                     
                (Details)                                                        
74: R61         Operating Leases - Schedule of operating lease      HTML     49K 
                liabilities (Details)                                            
75: R62         Accrued Professional Liabilities - Additional       HTML     37K 
                Information (Detail)                                             
76: R63         Accrued Professional Liabilities - Schedule of      HTML     45K 
                Accrued Professional Liability (Detail)                          
77: R64         Line of Credit, Long-Term Debt and Finance Lease    HTML    121K 
                Obligations - Additional Information (Detail)                    
78: R65         Line of Credit, Long-Term Debt and Finance Lease    HTML     40K 
                Obligations - Schedule of Long-Term Debt (Detail)                
79: R66         Line of Credit, Long-Term Debt and Finance Lease    HTML     36K 
                Obligations - Summary of Estimated Fair Value of                 
                Notes (Detail)                                                   
80: R67         Line of Credit, Long-Term Debt and Financial Lease  HTML     33K 
                Obligations - Schedule of Financial Lease                        
                Obligations (Detail)                                             
81: R68         Income Taxes - Summary of Components of Income Tax  HTML     50K 
                Provision (Detail)                                               
82: R69         Income Taxes - Additional Information (Detail)      HTML     75K 
83: R70         Income Taxes - Schedule of Differences Between      HTML     51K 
                Effective Rate and United States Federal Income                  
                Tax Statutory Rate (Detail)                                      
84: R71         Income Taxes - Significant Components of Deferred   HTML     70K 
                Income Tax Assets and Liabilities (Detail)                       
85: R72         Income Taxes - Schedule of Activity Related to      HTML     41K 
                Gross Unrecognized Tax Benefits (Detail)                         
86: R73         Common and Common Equivalent Shares - Schedule of   HTML     40K 
                Calculation of Shares Used in Basic and Diluted                  
                Net Income Per Share (Detail)                                    
87: R74         Stock Incentive Plans and Stock Purchase Plans -    HTML     90K 
                Additional Information (Detail)                                  
88: R75         Stock Incentive Plans and Stock Purchase Plans -    HTML     49K 
                Schedule of Restricted Stock and Deferred Stock                  
                Awards (Detail)                                                  
89: R76         Stock Incentive Plans and Stock Purchase Plans -    HTML     58K 
                Schedule of Activity and Certain Other Information               
                Related to Stock Option Awards (Detail)                          
90: R77         Common Stock Repurchase Programs - Additional       HTML     45K 
                Information (Detail)                                             
91: R78         Retirement Plans - Additional Information (Detail)  HTML     29K 
92: R79         Selected Quarterly Financial Information - Summary  HTML    134K 
                of Company's Selected Quarterly Financial                        
                Information (Detail)                                             
94: XML         IDEA XML File -- Filing Summary                      XML    176K 
13: XML         XBRL Instance -- d51794d10k_htm                      XML   2.22M 
93: EXCEL       IDEA Workbook of Financial Reports                  XLSX    117K 
 9: EX-101.CAL  XBRL Calculations -- md-20201231_cal                 XML    219K 
10: EX-101.DEF  XBRL Definitions -- md-20201231_def                  XML    605K 
11: EX-101.LAB  XBRL Labels -- md-20201231_lab                       XML   1.50M 
12: EX-101.PRE  XBRL Presentations -- md-20201231_pre                XML   1.09M 
 8: EX-101.SCH  XBRL Schema -- md-20201231                           XSD    213K 
95: JSON        XBRL Instance as JSON Data -- MetaLinks              462±   677K 
96: ZIP         XBRL Zipped Folder -- 0001193125-21-047064-xbrl      Zip    363K

‘EX-101.DEF’   —   XBRL Definitions — md-20201231_def

This Exhibit is an XBRL XML File.

                                                                                                                                                                                
<?xml version="1.0" encoding="windows-1252"?>
<!-- Generated by DFIN XBRL Instance Document - http://www.dfinsolutions.com/ - Version R3.0 - on 18-February-2021 [01:05:23] {AM} -->
<linkbase xmlns="http://www.xbrl.org/2003/linkbase" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd" xmlns:xbrldt="http://xbrl.org/2005/xbrldt">
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#ConsolidatedStatementsOfEquity" roleURI="http://www.mednax.com/role/ConsolidatedStatementsOfEquity"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#CoronavirusPandemicCovid19AdditionalInformationDetail" roleURI="http://www.mednax.com/role/CoronavirusPandemicCovid19AdditionalInformationDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#SummaryOfSignificantAccountingPoliciesAdditionalInformationDetail" roleURI="http://www.mednax.com/role/SummaryOfSignificantAccountingPoliciesAdditionalInformationDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#SummaryOfSignificantAccountingPoliciesScheduleOfNetRevenueByServiceLineDetail" roleURI="http://www.mednax.com/role/SummaryOfSignificantAccountingPoliciesScheduleOfNetRevenueByServiceLineDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#SummaryOfSignificantAccountingPoliciesScheduleOfFairValueOnARecurringBasisDetail" roleURI="http://www.mednax.com/role/SummaryOfSignificantAccountingPoliciesScheduleOfFairValueOnARecurringBasisDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#SummaryOfSignificantAccountingPoliciesScheduleOfFinancialInstrumentsThatAreNotCarriedAtFairValueDetail" roleURI="http://www.mednax.com/role/SummaryOfSignificantAccountingPoliciesScheduleOfFinancialInstrumentsThatAreNotCarriedAtFairValueDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#InvestmentsScheduleOfInvestmentsDetail" roleURI="http://www.mednax.com/role/InvestmentsScheduleOfInvestmentsDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#AccountsReceivableAndNetRevenueScheduleOfNetRevenueDetail" roleURI="http://www.mednax.com/role/AccountsReceivableAndNetRevenueScheduleOfNetRevenueDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#AccountsReceivableAndNetRevenueScheduleOfNetPatientServiceRevenueByTypeOfPayorDetail" roleURI="http://www.mednax.com/role/AccountsReceivableAndNetRevenueScheduleOfNetPatientServiceRevenueByTypeOfPayorDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#PropertyAndEquipmentAdditionalInformationDetail" roleURI="http://www.mednax.com/role/PropertyAndEquipmentAdditionalInformationDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#BusinessCombinationsAdditionalInformationDetail" roleURI="http://www.mednax.com/role/BusinessCombinationsAdditionalInformationDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#GoodwillAndIntangibleAssetsAdditionalInformationDetail" roleURI="http://www.mednax.com/role/GoodwillAndIntangibleAssetsAdditionalInformationDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#GoodwillAndIntangibleAssetsSummaryOfIntangibleAssetsNetDetail" roleURI="http://www.mednax.com/role/GoodwillAndIntangibleAssetsSummaryOfIntangibleAssetsNetDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#DiscontinuedOperationsAdditionalInformationDetail" roleURI="http://www.mednax.com/role/DiscontinuedOperationsAdditionalInformationDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#OperatingLeasesScheduleOfOperatingLeaseRelatedRightOfUseAssetsAndRelatedLiabilitiesRecordedOnTheCompanySBalanceSheetAndTheWeightedAverageRemainingLeaseTermAndDiscountRateDetails" roleURI="http://www.mednax.com/role/OperatingLeasesScheduleOfOperatingLeaseRelatedRightOfUseAssetsAndRelatedLiabilitiesRecordedOnTheCompanySBalanceSheetAndTheWeightedAverageRemainingLeaseTermAndDiscountRateDetails"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#OperatingLeasesScheduleOfLeaseCostsForOperatingLeasesDetails" roleURI="http://www.mednax.com/role/OperatingLeasesScheduleOfLeaseCostsForOperatingLeasesDetails"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#OperatingLeasesScheduleOfSupplementalCashFlowInformationRelatedToOperatingLeasesDetails" roleURI="http://www.mednax.com/role/OperatingLeasesScheduleOfSupplementalCashFlowInformationRelatedToOperatingLeasesDetails"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#OperatingLeasesScheduleOfOperatingLeaseLiabilitiesDetails" roleURI="http://www.mednax.com/role/OperatingLeasesScheduleOfOperatingLeaseLiabilitiesDetails"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#LineOfCreditLongTermDebtAndFinanceLeaseObligationsAdditionalInformationDetail" roleURI="http://www.mednax.com/role/LineOfCreditLongTermDebtAndFinanceLeaseObligationsAdditionalInformationDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#LineOfCreditLongTermDebtAndFinanceLeaseObligationsScheduleOfLongTermDebtDetail" roleURI="http://www.mednax.com/role/LineOfCreditLongTermDebtAndFinanceLeaseObligationsScheduleOfLongTermDebtDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#LineOfCreditLongTermDebtAndFinanceLeaseObligationsSummaryOfEstimatedFairValueOfNotesDetail" roleURI="http://www.mednax.com/role/LineOfCreditLongTermDebtAndFinanceLeaseObligationsSummaryOfEstimatedFairValueOfNotesDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#IncomeTaxesAdditionalInformationDetail" roleURI="http://www.mednax.com/role/IncomeTaxesAdditionalInformationDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#StockIncentivePlansAndStockPurchasePlansAdditionalInformationDetail" roleURI="http://www.mednax.com/role/StockIncentivePlansAndStockPurchasePlansAdditionalInformationDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#CommonStockRepurchaseProgramsAdditionalInformationDetail" roleURI="http://www.mednax.com/role/CommonStockRepurchaseProgramsAdditionalInformationDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#CoverPage" roleURI="http://www.mednax.com/role/CoverPage"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#ConsolidatedBalanceSheetsParenthetical" roleURI="http://www.mednax.com/role/ConsolidatedBalanceSheetsParenthetical"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#ConsolidatedStatementsOfIncome" roleURI="http://www.mednax.com/role/ConsolidatedStatementsOfIncome"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#ConsolidatedStatementsOfCashFlows" roleURI="http://www.mednax.com/role/ConsolidatedStatementsOfCashFlows"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#PropertyPlantAndEquipmentScheduleOfPropertyAndEquipmentDetail" roleURI="http://www.mednax.com/role/PropertyPlantAndEquipmentScheduleOfPropertyAndEquipmentDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#AccountsReceivableAndNetRevenueScheduleOfAccountsReceivableNetDetail" roleURI="http://www.mednax.com/role/AccountsReceivableAndNetRevenueScheduleOfAccountsReceivableNetDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#AccountsPayableAndAccruedExpensesScheduleOfAccountsPayableAndAccruedExpensesDetail" roleURI="http://www.mednax.com/role/AccountsPayableAndAccruedExpensesScheduleOfAccountsPayableAndAccruedExpensesDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#AccruedProfessionalLiabilitiesScheduleOfAccruedProfessionalLiabilityDetail" roleURI="http://www.mednax.com/role/AccruedProfessionalLiabilitiesScheduleOfAccruedProfessionalLiabilityDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#AccruedProfessionalLiabilitiesAdditionalInformationDetail" roleURI="http://www.mednax.com/role/AccruedProfessionalLiabilitiesAdditionalInformationDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#GoodwillAndIntangibleAssetsAmortizationExpensesForExistingIntangibleAssetsForTheNextFiveYearsDetail" roleURI="http://www.mednax.com/role/GoodwillAndIntangibleAssetsAmortizationExpensesForExistingIntangibleAssetsForTheNextFiveYearsDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#LineOfCreditLongTermDebtAndFinancialLeaseObligationsScheduleOfFinancialLeaseObligationsDetail" roleURI="http://www.mednax.com/role/LineOfCreditLongTermDebtAndFinancialLeaseObligationsScheduleOfFinancialLeaseObligationsDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#IncomeTaxesSummaryOfComponentsOfIncomeTaxProvisionDetail" roleURI="http://www.mednax.com/role/IncomeTaxesSummaryOfComponentsOfIncomeTaxProvisionDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#IncomeTaxesScheduleOfDifferencesBetweenEffectiveRateAndUnitedStatesFederalIncomeTaxStatutoryRateDetail" roleURI="http://www.mednax.com/role/IncomeTaxesScheduleOfDifferencesBetweenEffectiveRateAndUnitedStatesFederalIncomeTaxStatutoryRateDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#IncomeTaxesSignificantComponentsOfDeferredIncomeTaxAssetsAndLiabilitiesDetail" roleURI="http://www.mednax.com/role/IncomeTaxesSignificantComponentsOfDeferredIncomeTaxAssetsAndLiabilitiesDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#RetirementPlansAdditionalInformationDetail" roleURI="http://www.mednax.com/role/RetirementPlansAdditionalInformationDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#SelectedQuarterlyFinancialInformationSummaryOfCompanysSelectedQuarterlyFinancialInformationDetail" roleURI="http://www.mednax.com/role/SelectedQuarterlyFinancialInformationSummaryOfCompanysSelectedQuarterlyFinancialInformationDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#IncomeTaxesScheduleOfActivityRelatedToGrossUnrecognizedTaxBenefitsDetail" roleURI="http://www.mednax.com/role/IncomeTaxesScheduleOfActivityRelatedToGrossUnrecognizedTaxBenefitsDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#CommonAndCommonEquivalentSharesScheduleOfCalculationOfSharesUsedInBasicAndDilutedNetIncomePerShareDetail" roleURI="http://www.mednax.com/role/CommonAndCommonEquivalentSharesScheduleOfCalculationOfSharesUsedInBasicAndDilutedNetIncomePerShareDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#StockIncentivePlansAndStockPurchasePlansScheduleOfRestrictedStockAndDeferredStockAwardsDetail" roleURI="http://www.mednax.com/role/StockIncentivePlansAndStockPurchasePlansScheduleOfRestrictedStockAndDeferredStockAwardsDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#StockIncentivePlansAndStockPurchasePlansScheduleOfActivityAndCertainOtherInformationRelatedToStockOptionAwardsDetail" roleURI="http://www.mednax.com/role/StockIncentivePlansAndStockPurchasePlansScheduleOfActivityAndCertainOtherInformationRelatedToStockOptionAwardsDetail"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#General" roleURI="http://www.mednax.com/role/General"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#SummaryOfSignificantAccountingPolicies" roleURI="http://www.mednax.com/role/SummaryOfSignificantAccountingPolicies"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#SummaryOfSignificantAccountingPoliciesPolicies" roleURI="http://www.mednax.com/role/SummaryOfSignificantAccountingPoliciesPolicies"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#SummaryOfSignificantAccountingPoliciesTables" roleURI="http://www.mednax.com/role/SummaryOfSignificantAccountingPoliciesTables"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#Investments" roleURI="http://www.mednax.com/role/Investments"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#InvestmentsTables" roleURI="http://www.mednax.com/role/InvestmentsTables"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#AccountsReceivableAndNetRevenue" roleURI="http://www.mednax.com/role/AccountsReceivableAndNetRevenue"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#AccountsReceivableAndNetRevenueTables" roleURI="http://www.mednax.com/role/AccountsReceivableAndNetRevenueTables"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#AccountsPayableAndAccruedExpenses" roleURI="http://www.mednax.com/role/AccountsPayableAndAccruedExpenses"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#AccountsPayableAndAccruedExpensesTables" roleURI="http://www.mednax.com/role/AccountsPayableAndAccruedExpensesTables"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#AccruedProfessionalLiabilities" roleURI="http://www.mednax.com/role/AccruedProfessionalLiabilities"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#AccruedProfessionalLiabilitiesTables" roleURI="http://www.mednax.com/role/AccruedProfessionalLiabilitiesTables"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#LineOfCreditLongTermDebtAndFinanceLeaseObligations" roleURI="http://www.mednax.com/role/LineOfCreditLongTermDebtAndFinanceLeaseObligations"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#LineOfCreditLongTermDebtAndFinanceLeaseObligationsTables" roleURI="http://www.mednax.com/role/LineOfCreditLongTermDebtAndFinanceLeaseObligationsTables"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#CommonStockRepurchasePrograms" roleURI="http://www.mednax.com/role/CommonStockRepurchasePrograms"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#RetirementPlans" roleURI="http://www.mednax.com/role/RetirementPlans"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#CommitmentsAndContingencies" roleURI="http://www.mednax.com/role/CommitmentsAndContingencies"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#SelectedQuarterlyFinancialInformation" roleURI="http://www.mednax.com/role/SelectedQuarterlyFinancialInformation"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#SelectedQuarterlyFinancialInformationTables" roleURI="http://www.mednax.com/role/SelectedQuarterlyFinancialInformationTables"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#PropertyAndEquipment" roleURI="http://www.mednax.com/role/PropertyAndEquipment"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#PropertyAndEquipmentTables" roleURI="http://www.mednax.com/role/PropertyAndEquipmentTables"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#GoodwillAndIntangibleAssetsTables" roleURI="http://www.mednax.com/role/GoodwillAndIntangibleAssetsTables"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#IncomeTaxes" roleURI="http://www.mednax.com/role/IncomeTaxes"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#IncomeTaxesTables" roleURI="http://www.mednax.com/role/IncomeTaxesTables"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#CommonAndCommonEquivalentShares" roleURI="http://www.mednax.com/role/CommonAndCommonEquivalentShares"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#CommonAndCommonEquivalentSharesTables" roleURI="http://www.mednax.com/role/CommonAndCommonEquivalentSharesTables"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#StockIncentivePlansAndStockPurchasePlans" roleURI="http://www.mednax.com/role/StockIncentivePlansAndStockPurchasePlans"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#StockIncentivePlansAndStockPurchasePlansTables" roleURI="http://www.mednax.com/role/StockIncentivePlansAndStockPurchasePlansTables"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#ConsolidatedBalanceSheets" roleURI="http://www.mednax.com/role/ConsolidatedBalanceSheets"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#OperatingLeases" roleURI="http://www.mednax.com/role/OperatingLeases"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#OperatingLeasesTables" roleURI="http://www.mednax.com/role/OperatingLeasesTables"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#DiscontinuedOperations" roleURI="http://www.mednax.com/role/DiscontinuedOperations"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#BusinessCombinations" roleURI="http://www.mednax.com/role/BusinessCombinations"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#GoodwillAndIntangibleAssets" roleURI="http://www.mednax.com/role/GoodwillAndIntangibleAssets"/>
<roleRef xlink:type="simple" xlink:href="md-20201231.xsd#CoronavirusPandemicCovid19" roleURI="http://www.mednax.com/role/CoronavirusPandemicCovid19"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
<arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/notAll" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#notAll"/>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/ConsolidatedStatementsOfEquity">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_98"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_113"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_113" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="loc_us-gaap_NetIncomeLoss_106"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_us-gaap_NetIncomeLoss_106" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharesIssued" xlink:label="loc_us-gaap_SharesIssued_105"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_us-gaap_SharesIssued_105" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_99"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_us-gaap_StatementTable_99" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_97"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_99" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_97" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_96"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_97" xlink:to="loc_us-gaap_EquityComponentDomain_96" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="loc_us-gaap_EquityComponentDomain_96_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_97" xlink:to="loc_us-gaap_EquityComponentDomain_96_default" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_100"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_96" xlink:to="loc_us-gaap_CommonStockMember_100" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_RetainedEarningsAndAccumulatedOtherComprehensiveIncomeMember" xlink:label="loc_md_RetainedEarningsAndAccumulatedOtherComprehensiveIncomeMember_102"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_96" xlink:to="loc_md_RetainedEarningsAndAccumulatedOtherComprehensiveIncomeMember_102" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_101"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_96" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_101" use="optional" order="10"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_104"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_104" use="optional" order="11"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited_117"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesRestrictedStockAwardForfeited_117" use="optional" order="12"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_108"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_108" use="optional" order="13"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross_812923"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensationGross_812923" use="optional" order="14"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_StockIssuedDuringPeriodSharesStockSwaps" xlink:label="loc_md_StockIssuedDuringPeriodSharesStockSwaps_115"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_md_StockIssuedDuringPeriodSharesStockSwaps_115" use="optional" order="15"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardForfeitures" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardForfeitures_116"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueRestrictedStockAwardForfeitures_116" use="optional" order="16"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_107"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensation_107" use="optional" order="17"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationGross" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationGross_812920"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueShareBasedCompensationGross_812920" use="optional" order="18"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_StockIssuedDuringPeriodValueStockSwaps" xlink:label="loc_md_StockIssuedDuringPeriodValueStockSwaps_114"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_md_StockIssuedDuringPeriodValueStockSwaps_114" use="optional" order="19"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodShares" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_119"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_119" use="optional" order="20"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodValue" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue_118"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodValue_118" use="optional" order="21"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_393245"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax_393245" use="optional" order="22"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance" xlink:label="loc_us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance_812916"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_98" xlink:to="loc_us-gaap_NoncontrollingInterestIncreaseFromSubsidiaryEquityIssuance_812916" use="optional" order="23"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/CoronavirusPandemicCovid19AdditionalInformationDetail">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_812905"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_812902"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_812905" xlink:to="loc_us-gaap_StatementTable_812902" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ExtraordinaryItemsAxis" xlink:label="loc_md_ExtraordinaryItemsAxis_812907"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_812902" xlink:to="loc_md_ExtraordinaryItemsAxis_812907" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ExtraordinaryItemsDomain" xlink:label="loc_md_ExtraordinaryItemsDomain_812908"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_md_ExtraordinaryItemsAxis_812907" xlink:to="loc_md_ExtraordinaryItemsDomain_812908" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ExtraordinaryItemsDomain" xlink:label="loc_md_ExtraordinaryItemsDomain_812908_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_md_ExtraordinaryItemsAxis_812907" xlink:to="loc_md_ExtraordinaryItemsDomain_812908_default" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_CovidNinenteenMember" xlink:label="loc_md_CovidNinenteenMember_812909"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_ExtraordinaryItemsDomain_812908" xlink:to="loc_md_CovidNinenteenMember_812909" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualAxis" xlink:label="loc_srt_TitleOfIndividualAxis_812910"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_812902" xlink:to="loc_srt_TitleOfIndividualAxis_812910" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_812911"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_812910" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_812911" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_812911_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_812910" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_812911_default" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ExecutiveOfficerMember" xlink:label="loc_srt_ExecutiveOfficerMember_812912"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_812911" xlink:to="loc_srt_ExecutiveOfficerMember_812912" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementScenarioAxis" xlink:label="loc_srt_StatementScenarioAxis_812913"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_812902" xlink:to="loc_srt_StatementScenarioAxis_812913" use="optional" order="10"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srt_ScenarioUnspecifiedDomain_812914"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_812913" xlink:to="loc_srt_ScenarioUnspecifiedDomain_812914" use="optional" order="11"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srt_ScenarioUnspecifiedDomain_812914_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_812913" xlink:to="loc_srt_ScenarioUnspecifiedDomain_812914_default" use="optional" order="12"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ForecastForSecondAndThirdQuartersOf2020Member" xlink:label="loc_md_ForecastForSecondAndThirdQuartersOf2020Member_812915"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_812914" xlink:to="loc_md_ForecastForSecondAndThirdQuartersOf2020Member_812915" use="optional" order="13"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ForecastForFourthQuarterOf2020Member" xlink:label="loc_md_ForecastForFourthQuarterOf2020Member_812917"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_812914" xlink:to="loc_md_ForecastForFourthQuarterOf2020Member_812917" use="optional" order="14"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ForecastForFirstQuarterOf2021Member" xlink:label="loc_md_ForecastForFirstQuarterOf2021Member_812918"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_812914" xlink:to="loc_md_ForecastForFirstQuarterOf2021Member_812918" use="optional" order="15"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ForecastForSecondQuarterOf2021Member" xlink:label="loc_md_ForecastForSecondQuarterOf2021Member_812919"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_812914" xlink:to="loc_md_ForecastForSecondQuarterOf2021Member_812919" use="optional" order="16"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ForecastForThirdQuarterOf2021Member" xlink:label="loc_md_ForecastForThirdQuarterOf2021Member_825804"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_812914" xlink:to="loc_md_ForecastForThirdQuarterOf2021Member_825804" use="optional" order="17"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_812921"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_812902" xlink:to="loc_us-gaap_CreditFacilityAxis_812921" use="optional" order="18"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_812922"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_812921" xlink:to="loc_us-gaap_CreditFacilityDomain_812922" use="optional" order="19"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_812922_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_812921" xlink:to="loc_us-gaap_CreditFacilityDomain_812922_default" use="optional" order="20"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_CreditAgreementMember" xlink:label="loc_md_CreditAgreementMember_812924"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_812922" xlink:to="loc_md_CreditAgreementMember_812924" use="optional" order="21"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LetterOfCreditMember" xlink:label="loc_us-gaap_LetterOfCreditMember_812925"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_812922" xlink:to="loc_us-gaap_LetterOfCreditMember_812925" use="optional" order="22"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_812927"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_812902" xlink:to="loc_srt_RangeAxis_812927" use="optional" order="23"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_813359"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_812927" xlink:to="loc_srt_RangeMember_813359" use="optional" order="24"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_813359_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_812927" xlink:to="loc_srt_RangeMember_813359_default" use="optional" order="25"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_813360"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_813359" xlink:to="loc_srt_MaximumMember_813360" use="optional" order="26"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_813361"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_813359" xlink:to="loc_srt_MinimumMember_813361" use="optional" order="27"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeographicDistributionAxis" xlink:label="loc_us-gaap_GeographicDistributionAxis_812931"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_812902" xlink:to="loc_us-gaap_GeographicDistributionAxis_812931" use="optional" order="28"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeographicDistributionDomain" xlink:label="loc_us-gaap_GeographicDistributionDomain_812932"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_GeographicDistributionAxis_812931" xlink:to="loc_us-gaap_GeographicDistributionDomain_812932" use="optional" order="29"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GeographicDistributionDomain" xlink:label="loc_us-gaap_GeographicDistributionDomain_812932_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_GeographicDistributionAxis_812931" xlink:to="loc_us-gaap_GeographicDistributionDomain_812932_default" use="optional" order="30"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_RuralAreaMember" xlink:label="loc_md_RuralAreaMember_812934"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GeographicDistributionDomain_812932" xlink:to="loc_md_RuralAreaMember_812934" use="optional" order="31"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_812935"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_812902" xlink:to="loc_us-gaap_DebtInstrumentAxis_812935" use="optional" order="32"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_812936"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_812935" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_812936" use="optional" order="33"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_812936_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_812935" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_812936_default" use="optional" order="34"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_Seniorunsecurdnotes2023Member" xlink:label="loc_md_Seniorunsecurdnotes2023Member_812937"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_812936" xlink:to="loc_md_Seniorunsecurdnotes2023Member_812937" use="optional" order="35"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_Seniorunsecurdnotes2027Member" xlink:label="loc_md_Seniorunsecurdnotes2027Member_812938"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_812936" xlink:to="loc_md_Seniorunsecurdnotes2027Member_812938" use="optional" order="36"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_PercentageIncreaseDecreaseInSalaryAndWage" xlink:label="loc_md_PercentageIncreaseDecreaseInSalaryAndWage_812939"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_812905" xlink:to="loc_md_PercentageIncreaseDecreaseInSalaryAndWage_812939" use="optional" order="37"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_SupplementaryLeverageRatioRequired" xlink:label="loc_md_SupplementaryLeverageRatioRequired_812941"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_812905" xlink:to="loc_md_SupplementaryLeverageRatioRequired_812941" use="optional" order="38"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ContributionsInAidOfReimbursementOfLostRevenue" xlink:label="loc_md_ContributionsInAidOfReimbursementOfLostRevenue_812943"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_812905" xlink:to="loc_md_ContributionsInAidOfReimbursementOfLostRevenue_812943" use="optional" order="39"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ProceedsFromContributionInAidOfReimbursementOfLostRevenue" xlink:label="loc_md_ProceedsFromContributionInAidOfReimbursementOfLostRevenue_812944"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_812905" xlink:to="loc_md_ProceedsFromContributionInAidOfReimbursementOfLostRevenue_812944" use="optional" order="40"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_PercentageOfDeferredPaymentOfSocialSecurityTaxes" xlink:label="loc_md_PercentageOfDeferredPaymentOfSocialSecurityTaxes_812945"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_812905" xlink:to="loc_md_PercentageOfDeferredPaymentOfSocialSecurityTaxes_812945" use="optional" order="41"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateDuringPeriod" xlink:label="loc_us-gaap_DebtInstrumentInterestRateDuringPeriod_812946"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_812905" xlink:to="loc_us-gaap_DebtInstrumentInterestRateDuringPeriod_812946" use="optional" order="42"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_812947"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_812905" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_812947" use="optional" order="43"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_812948"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_812905" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_812948" use="optional" order="44"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_DeemedConsolidatedEarningsBeforeInterestTaxesDepreciationAndAmortization" xlink:label="loc_md_DeemedConsolidatedEarningsBeforeInterestTaxesDepreciationAndAmortization_825800"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_812905" xlink:to="loc_md_DeemedConsolidatedEarningsBeforeInterestTaxesDepreciationAndAmortization_825800" use="optional" order="45"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_LineOfCreditFacilityMinimumAvailabilityUnderCreditAgreement" xlink:label="loc_md_LineOfCreditFacilityMinimumAvailabilityUnderCreditAgreement_825803"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_812905" xlink:to="loc_md_LineOfCreditFacilityMinimumAvailabilityUnderCreditAgreement_825803" use="optional" order="46"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/SummaryOfSignificantAccountingPoliciesAdditionalInformationDetail">
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_SummaryOfSignificantAccountingPoliciesLineItems" xlink:label="loc_md_SummaryOfSignificantAccountingPoliciesLineItems_187"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_BusinessCombinationContingentConsiderationArrangementsTimePeriod" xlink:label="loc_md_BusinessCombinationContingentConsiderationArrangementsTimePeriod_207"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_SummaryOfSignificantAccountingPoliciesLineItems_187" xlink:to="loc_md_BusinessCombinationContingentConsiderationArrangementsTimePeriod_207" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_CashAndCashEquivalentsMaturityDescription" xlink:label="loc_md_CashAndCashEquivalentsMaturityDescription_203"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_SummaryOfSignificantAccountingPoliciesLineItems_187" xlink:to="loc_md_CashAndCashEquivalentsMaturityDescription_203" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_202"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_SummaryOfSignificantAccountingPoliciesLineItems_187" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_202" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquityMethodInvestmentOwnershipPercentage" xlink:label="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_201"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_SummaryOfSignificantAccountingPoliciesLineItems_187" xlink:to="loc_us-gaap_EquityMethodInvestmentOwnershipPercentage_201" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetUsefulLife" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_208"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_SummaryOfSignificantAccountingPoliciesLineItems_187" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetUsefulLife_208" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_206"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_SummaryOfSignificantAccountingPoliciesLineItems_187" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_206" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ShortTermInvestmentMaturityPeriod" xlink:label="loc_md_ShortTermInvestmentMaturityPeriod_205"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_SummaryOfSignificantAccountingPoliciesLineItems_187" xlink:to="loc_md_ShortTermInvestmentMaturityPeriod_205" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_SummaryOfSignificantAccountingPoliciesTable" xlink:label="loc_md_SummaryOfSignificantAccountingPoliciesTable_188"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_md_SummaryOfSignificantAccountingPoliciesLineItems_187" xlink:to="loc_md_SummaryOfSignificantAccountingPoliciesTable_188" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_176"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_SummaryOfSignificantAccountingPoliciesTable_188" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_176" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_175"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_176" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_175" use="optional" order="10"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_175_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_176" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_175_default" use="optional" order="11"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AccountsReceivableMember" xlink:label="loc_us-gaap_AccountsReceivableMember_189"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_175" xlink:to="loc_us-gaap_AccountsReceivableMember_189" use="optional" order="12"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_177"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_SummaryOfSignificantAccountingPoliciesTable_188" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_177" use="optional" order="13"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_178"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_177" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_178" use="optional" order="14"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_178_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_177" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_178_default" use="optional" order="15"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GovernmentContractsConcentrationRiskMember" xlink:label="loc_us-gaap_GovernmentContractsConcentrationRiskMember_190"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_178" xlink:to="loc_us-gaap_GovernmentContractsConcentrationRiskMember_190" use="optional" order="16"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_179"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_SummaryOfSignificantAccountingPoliciesTable_188" xlink:to="loc_us-gaap_CreditFacilityAxis_179" use="optional" order="17"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_180"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_179" xlink:to="loc_us-gaap_CreditFacilityDomain_180" use="optional" order="18"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_180_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_179" xlink:to="loc_us-gaap_CreditFacilityDomain_180_default" use="optional" order="19"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_182"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_SummaryOfSignificantAccountingPoliciesTable_188" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_182" use="optional" order="20"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_183"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_182" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_183" use="optional" order="21"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_183_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_182" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_183_default" use="optional" order="22"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BuildingMember" xlink:label="loc_us-gaap_BuildingMember_194"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_183" xlink:to="loc_us-gaap_BuildingMember_194" use="optional" order="23"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ComputerEquipmentMember" xlink:label="loc_us-gaap_ComputerEquipmentMember_196"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_183" xlink:to="loc_us-gaap_ComputerEquipmentMember_196" use="optional" order="24"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EquipmentMember" xlink:label="loc_us-gaap_EquipmentMember_195"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_183" xlink:to="loc_us-gaap_EquipmentMember_195" use="optional" order="25"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="loc_us-gaap_FurnitureAndFixturesMember_198"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_183" xlink:to="loc_us-gaap_FurnitureAndFixturesMember_198" use="optional" order="26"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SoftwareAndSoftwareDevelopmentCostsMember" xlink:label="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_197"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_183" xlink:to="loc_us-gaap_SoftwareAndSoftwareDevelopmentCostsMember_197" use="optional" order="27"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_184"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_SummaryOfSignificantAccountingPoliciesTable_188" xlink:to="loc_srt_RangeAxis_184" use="optional" order="28"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_185"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_184" xlink:to="loc_srt_RangeMember_185" use="optional" order="29"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_185_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_184" xlink:to="loc_srt_RangeMember_185_default" use="optional" order="30"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_199"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_185" xlink:to="loc_srt_MaximumMember_199" use="optional" order="31"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_200"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_185" xlink:to="loc_srt_MinimumMember_200" use="optional" order="32"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis" xlink:label="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_186"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_SummaryOfSignificantAccountingPoliciesTable_188" xlink:to="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_186" use="optional" order="33"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_181"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_186" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_181" use="optional" order="34"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_EquityMethodInvesteeNameDomain" xlink:label="loc_srt_EquityMethodInvesteeNameDomain_181_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis_186" xlink:to="loc_srt_EquityMethodInvesteeNameDomain_181_default" use="optional" order="35"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_UnnamedCorporateJointVentureOneMember" xlink:label="loc_md_UnnamedCorporateJointVentureOneMember_193"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_181" xlink:to="loc_md_UnnamedCorporateJointVentureOneMember_193" use="optional" order="36"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_UnnamedCorporateJointVentureTwoMember" xlink:label="loc_md_UnnamedCorporateJointVentureTwoMember_554497"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_EquityMethodInvesteeNameDomain_181" xlink:to="loc_md_UnnamedCorporateJointVentureTwoMember_554497" use="optional" order="37"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_554481"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_SummaryOfSignificantAccountingPoliciesTable_188" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_554481" use="optional" order="38"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_554482"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_554481" xlink:to="loc_us-gaap_SegmentDomain_554482" use="optional" order="39"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_554482_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_554481" xlink:to="loc_us-gaap_SegmentDomain_554482_default" use="optional" order="40"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/SummaryOfSignificantAccountingPoliciesScheduleOfNetRevenueByServiceLineDetail">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_222"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_231"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_222" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_231" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_221"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_222" xlink:to="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_221" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_216"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_221" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_216" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_215"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_216" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_215" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_215_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_216" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_215_default" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_SalesAndRevenueServicesNetMember" xlink:label="loc_md_SalesAndRevenueServicesNetMember_223"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_215" xlink:to="loc_md_SalesAndRevenueServicesNetMember_223" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_217"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_221" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_217" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_218"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_217" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_218" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_218_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_217" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_218_default" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProductConcentrationRiskMember" xlink:label="loc_us-gaap_ProductConcentrationRiskMember_224"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_218" xlink:to="loc_us-gaap_ProductConcentrationRiskMember_224" use="optional" order="10"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srt_ProductOrServiceAxis_219"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_221" xlink:to="loc_srt_ProductOrServiceAxis_219" use="optional" order="11"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_220"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_219" xlink:to="loc_srt_ProductsAndServicesDomain_220" use="optional" order="12"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_220_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_219" xlink:to="loc_srt_ProductsAndServicesDomain_220_default" use="optional" order="13"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_MaternalFetalMedicineMember" xlink:label="loc_md_MaternalFetalMedicineMember_228"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_220" xlink:to="loc_md_MaternalFetalMedicineMember_228" use="optional" order="14"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_NeonatologyAndOtherPediatricSubspecialtiesMember" xlink:label="loc_md_NeonatologyAndOtherPediatricSubspecialtiesMember_225"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_220" xlink:to="loc_md_NeonatologyAndOtherPediatricSubspecialtiesMember_225" use="optional" order="15"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_PediatricCardiologyMember" xlink:label="loc_md_PediatricCardiologyMember_230"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_220" xlink:to="loc_md_PediatricCardiologyMember_230" use="optional" order="16"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/SummaryOfSignificantAccountingPoliciesScheduleOfFairValueOnARecurringBasisDetail">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_393319"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_393316"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_393319" xlink:to="loc_us-gaap_StatementTable_393316" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_393317"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_393316" xlink:to="loc_us-gaap_StatementClassOfStockAxis_393317" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_393318"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_393317" xlink:to="loc_us-gaap_ClassOfStockDomain_393318" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_393318_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_393317" xlink:to="loc_us-gaap_ClassOfStockDomain_393318_default" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_395190"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_393316" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_395190" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_395283"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_395190" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_395283" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_395283_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_395190" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_395283_default" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="loc_us-gaap_FairValueInputsLevel1Member_395284"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_395283" xlink:to="loc_us-gaap_FairValueInputsLevel1Member_395284" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_395285"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_395283" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_395285" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis_395202"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_393316" xlink:to="loc_us-gaap_FairValueByMeasurementFrequencyAxis_395202" use="optional" order="10"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_395203"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_395202" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_395203" use="optional" order="11"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="loc_us-gaap_FairValueMeasurementFrequencyDomain_395203_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis_395202" xlink:to="loc_us-gaap_FairValueMeasurementFrequencyDomain_395203_default" use="optional" order="12"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsRecurringMember_395287"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementFrequencyDomain_395203" xlink:to="loc_us-gaap_FairValueMeasurementsRecurringMember_395287" use="optional" order="13"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetsFairValueDisclosureAbstract" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_393322"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393319" xlink:to="loc_us-gaap_AssetsFairValueDisclosureAbstract_393322" use="optional" order="14"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_MoneyMarketFundsFairValueDisclosure" xlink:label="loc_md_MoneyMarketFundsFairValueDisclosure_393323"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_393322" xlink:to="loc_md_MoneyMarketFundsFairValueDisclosure_393323" use="optional" order="15"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentsFairValueDisclosure" xlink:label="loc_us-gaap_InvestmentsFairValueDisclosure_393325"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_393322" xlink:to="loc_us-gaap_InvestmentsFairValueDisclosure_393325" use="optional" order="16"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_MutualFundsFairValueDisclosure" xlink:label="loc_md_MutualFundsFairValueDisclosure_499981"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_393322" xlink:to="loc_md_MutualFundsFairValueDisclosure_499981" use="optional" order="17"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/SummaryOfSignificantAccountingPoliciesScheduleOfFinancialInstrumentsThatAreNotCarriedAtFairValueDetail">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_393336"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_393333"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_393336" xlink:to="loc_us-gaap_StatementTable_393333" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_393334"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_393333" xlink:to="loc_us-gaap_StatementClassOfStockAxis_393334" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_393335"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_393334" xlink:to="loc_us-gaap_ClassOfStockDomain_393335" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_393335_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_393334" xlink:to="loc_us-gaap_ClassOfStockDomain_393335_default" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_395206"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_393333" xlink:to="loc_us-gaap_DebtInstrumentAxis_395206" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_395207"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_395206" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_395207" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_395207_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_395206" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_395207_default" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_TwoThousandTwentyThreeMember" xlink:label="loc_md_TwoThousandTwentyThreeMember_395214"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_395207" xlink:to="loc_md_TwoThousandTwentyThreeMember_395214" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_TwoThousandTwentySevenMember" xlink:label="loc_md_TwoThousandTwentySevenMember_395215"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_395207" xlink:to="loc_md_TwoThousandTwentySevenMember_395215" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesAbstract" xlink:label="loc_us-gaap_LiabilitiesAbstract_393340"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393336" xlink:to="loc_us-gaap_LiabilitiesAbstract_393340" use="optional" order="10"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesPayable" xlink:label="loc_us-gaap_NotesPayable_393341"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesAbstract_393340" xlink:to="loc_us-gaap_NotesPayable_393341" use="optional" order="11"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_393390"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393336" xlink:to="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_393390" use="optional" order="12"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesPayableFairValueDisclosure" xlink:label="loc_us-gaap_NotesPayableFairValueDisclosure_393391"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_393390" xlink:to="loc_us-gaap_NotesPayableFairValueDisclosure_393391" use="optional" order="13"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/InvestmentsScheduleOfInvestmentsDetail">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_236"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfHeldToMaturitySecuritiesTable" xlink:label="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_237"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_236" xlink:to="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_237" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeAxis" xlink:label="loc_us-gaap_InvestmentTypeAxis_234"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_237" xlink:to="loc_us-gaap_InvestmentTypeAxis_234" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_235"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_InvestmentTypeAxis_234" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_235" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_InvestmentTypeCategorizationMember" xlink:label="loc_us-gaap_InvestmentTypeCategorizationMember_235_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_InvestmentTypeAxis_234" xlink:to="loc_us-gaap_InvestmentTypeCategorizationMember_235_default" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CertificatesOfDepositMember" xlink:label="loc_us-gaap_CertificatesOfDepositMember_240"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_235" xlink:to="loc_us-gaap_CertificatesOfDepositMember_240" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember" xlink:label="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_239"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_235" xlink:to="loc_us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember_239" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USTreasurySecuritiesMember" xlink:label="loc_us-gaap_USTreasurySecuritiesMember_812988"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_235" xlink:to="loc_us-gaap_USTreasurySecuritiesMember_812988" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_238"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_235" xlink:to="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember_238" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllOtherCorporateBondsMember" xlink:label="loc_us-gaap_AllOtherCorporateBondsMember_554131"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_InvestmentTypeCategorizationMember_235" xlink:to="loc_us-gaap_AllOtherCorporateBondsMember_554131" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AvailableForSaleSecurities" xlink:label="loc_us-gaap_AvailableForSaleSecurities_813378"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_236" xlink:to="loc_us-gaap_AvailableForSaleSecurities_813378" use="optional" order="10"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/AccountsReceivableAndNetRevenueScheduleOfNetRevenueDetail">
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ScheduleOfFinancingReceivablesLineItems" xlink:label="loc_md_ScheduleOfFinancingReceivablesLineItems_259"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisaggregationOfRevenueAbstract" xlink:label="loc_us-gaap_DisaggregationOfRevenueAbstract_255"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_ScheduleOfFinancingReceivablesLineItems_259" xlink:to="loc_us-gaap_DisaggregationOfRevenueAbstract_255" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xlink:label="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_260"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueAbstract_255" xlink:to="loc_us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_260" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable" xlink:label="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_258"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_md_ScheduleOfFinancingReceivablesLineItems_259" xlink:to="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_258" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="loc_srt_ProductOrServiceAxis_256"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAccountsNotesLoansAndFinancingReceivableTable_258" xlink:to="loc_srt_ProductOrServiceAxis_256" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_257"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ProductOrServiceAxis_256" xlink:to="loc_srt_ProductsAndServicesDomain_257" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="loc_srt_ProductsAndServicesDomain_257_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ProductOrServiceAxis_256" xlink:to="loc_srt_ProductsAndServicesDomain_257_default" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HealthCarePatientServiceMember" xlink:label="loc_us-gaap_HealthCarePatientServiceMember_261"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_257" xlink:to="loc_us-gaap_HealthCarePatientServiceMember_261" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_HospitalsContractsMember" xlink:label="loc_md_HospitalsContractsMember_262"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_257" xlink:to="loc_md_HospitalsContractsMember_262" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProductAndServiceOtherMember" xlink:label="loc_us-gaap_ProductAndServiceOtherMember_395272"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ProductsAndServicesDomain_257" xlink:to="loc_us-gaap_ProductAndServiceOtherMember_395272" use="optional" order="9"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/AccountsReceivableAndNetRevenueScheduleOfNetPatientServiceRevenueByTypeOfPayorDetail">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HealthCareOrganizationReceivableAndRevenueDisclosuresLineItems" xlink:label="loc_us-gaap_HealthCareOrganizationReceivableAndRevenueDisclosuresLineItems_266"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfRevenueSourcesHealthCareOrganizationTable" xlink:label="loc_us-gaap_ScheduleOfRevenueSourcesHealthCareOrganizationTable_269"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_HealthCareOrganizationReceivableAndRevenueDisclosuresLineItems_266" xlink:to="loc_us-gaap_ScheduleOfRevenueSourcesHealthCareOrganizationTable_269" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HealthCareOrganizationRevenueSourcesAxis" xlink:label="loc_us-gaap_HealthCareOrganizationRevenueSourcesAxis_267"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRevenueSourcesHealthCareOrganizationTable_269" xlink:to="loc_us-gaap_HealthCareOrganizationRevenueSourcesAxis_267" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HealthCareOrganizationRevenueSourcesDomain" xlink:label="loc_us-gaap_HealthCareOrganizationRevenueSourcesDomain_268"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_HealthCareOrganizationRevenueSourcesAxis_267" xlink:to="loc_us-gaap_HealthCareOrganizationRevenueSourcesDomain_268" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_HealthCareOrganizationRevenueSourcesDomain" xlink:label="loc_us-gaap_HealthCareOrganizationRevenueSourcesDomain_268_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_HealthCareOrganizationRevenueSourcesAxis_267" xlink:to="loc_us-gaap_HealthCareOrganizationRevenueSourcesDomain_268_default" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SelfPayMember" xlink:label="loc_us-gaap_SelfPayMember_274"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HealthCareOrganizationRevenueSourcesDomain_268" xlink:to="loc_us-gaap_SelfPayMember_274" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ContractedManagedCareMember" xlink:label="loc_md_ContractedManagedCareMember_271"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HealthCareOrganizationRevenueSourcesDomain_268" xlink:to="loc_md_ContractedManagedCareMember_271" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GovernmentMember" xlink:label="loc_us-gaap_GovernmentMember_272"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HealthCareOrganizationRevenueSourcesDomain_268" xlink:to="loc_us-gaap_GovernmentMember_272" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ThirdPartyPayorMember" xlink:label="loc_us-gaap_ThirdPartyPayorMember_273"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HealthCareOrganizationRevenueSourcesDomain_268" xlink:to="loc_us-gaap_ThirdPartyPayorMember_273" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_PercentageOfNetPatientServiceRevenueByTypeOfPayor" xlink:label="loc_md_PercentageOfNetPatientServiceRevenueByTypeOfPayor_270"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_HealthCareOrganizationReceivableAndRevenueDisclosuresLineItems_266" xlink:to="loc_md_PercentageOfNetPatientServiceRevenueByTypeOfPayor_270" use="optional" order="9"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/PropertyAndEquipmentAdditionalInformationDetail">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_290"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Depreciation" xlink:label="loc_us-gaap_Depreciation_295"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_290" xlink:to="loc_us-gaap_Depreciation_295" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_292"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_290" xlink:to="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_292" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_289"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_292" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_289" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_291"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_289" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_291" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_291_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_289" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_291_default" use="optional" order="5"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/BusinessCombinationsAdditionalInformationDetail">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionLineItems" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_393273"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_393269"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_393273" xlink:to="loc_us-gaap_StatementTable_393269" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_393270"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_393269" xlink:to="loc_us-gaap_StatementClassOfStockAxis_393270" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_393271"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_393270" xlink:to="loc_us-gaap_ClassOfStockDomain_393271" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_393271_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_393270" xlink:to="loc_us-gaap_ClassOfStockDomain_393271_default" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_393276"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_393269" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_393276" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_393277"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_393276" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_393277" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_393277_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_393276" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_393277_default" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_PhysicianGroupMember" xlink:label="loc_md_PhysicianGroupMember_393278"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_393277" xlink:to="loc_md_PhysicianGroupMember_393278" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_PediatricSubspecialtyPracticeMember" xlink:label="loc_md_PediatricSubspecialtyPracticeMember_812995"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_393277" xlink:to="loc_md_PediatricSubspecialtyPracticeMember_812995" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_DeferredtaxassetsAxis" xlink:label="loc_md_DeferredtaxassetsAxis_812997"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_393269" xlink:to="loc_md_DeferredtaxassetsAxis_812997" use="optional" order="10"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_DeferredtaxassetsgoodwillDomain" xlink:label="loc_md_DeferredtaxassetsgoodwillDomain_812998"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_md_DeferredtaxassetsAxis_812997" xlink:to="loc_md_DeferredtaxassetsgoodwillDomain_812998" use="optional" order="11"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_DeferredtaxassetsgoodwillDomain" xlink:label="loc_md_DeferredtaxassetsgoodwillDomain_812998_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_md_DeferredtaxassetsAxis_812997" xlink:to="loc_md_DeferredtaxassetsgoodwillDomain_812998_default" use="optional" order="12"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationConsiderationTransferred1" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_393274"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_393273" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_393274" use="optional" order="13"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_GoodwillAcquiredDuringPeriod" xlink:label="loc_us-gaap_GoodwillAcquiredDuringPeriod_393275"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_393273" xlink:to="loc_us-gaap_GoodwillAcquiredDuringPeriod_393275" use="optional" order="14"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_393279"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_393273" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_393279" use="optional" order="15"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsForPreviousAcquisition" xlink:label="loc_us-gaap_PaymentsForPreviousAcquisition_393280"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_393273" xlink:to="loc_us-gaap_PaymentsForPreviousAcquisition_393280" use="optional" order="16"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_NumberOfPhysicianGroupPracticesAcquired" xlink:label="loc_md_NumberOfPhysicianGroupPracticesAcquired_395265"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_393273" xlink:to="loc_md_NumberOfPhysicianGroupPracticesAcquired_395265" use="optional" order="17"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_NumberOfNeonatologyPracticesAcquired" xlink:label="loc_md_NumberOfNeonatologyPracticesAcquired_395266"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_393273" xlink:to="loc_md_NumberOfNeonatologyPracticesAcquired_395266" use="optional" order="18"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_NumberOfPediatricSubspecialtyPracticesAcquired" xlink:label="loc_md_NumberOfPediatricSubspecialtyPracticesAcquired_395267"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_393273" xlink:to="loc_md_NumberOfPediatricSubspecialtyPracticesAcquired_395267" use="optional" order="19"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_NumberOfRadiologyPracticesAcquired" xlink:label="loc_md_NumberOfRadiologyPracticesAcquired_395268"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_393273" xlink:to="loc_md_NumberOfRadiologyPracticesAcquired_395268" use="optional" order="20"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:label="loc_us-gaap_PaymentsToAcquireBusinessesGross_499982"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_393273" xlink:to="loc_us-gaap_PaymentsToAcquireBusinessesGross_499982" use="optional" order="21"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_AccruedPurchaseConsideration" xlink:label="loc_md_AccruedPurchaseConsideration_499983"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_393273" xlink:to="loc_md_AccruedPurchaseConsideration_499983" use="optional" order="22"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_554191"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_393273" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssets_554191" use="optional" order="23"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_574648"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_393273" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_574648" use="optional" order="24"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/GoodwillAndIntangibleAssetsAdditionalInformationDetail">
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_GoodwillAndOtherIntangibleAssetsLineItems" xlink:label="loc_md_GoodwillAndOtherIntangibleAssetsLineItems_331"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="loc_us-gaap_AmortizationOfIntangibleAssets_341"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_GoodwillAndOtherIntangibleAssetsLineItems_331" xlink:to="loc_us-gaap_AmortizationOfIntangibleAssets_341" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_332"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_md_GoodwillAndOtherIntangibleAssetsLineItems_331" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_332" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_329"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_332" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_329" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_330"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_329" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_330" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_330_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_329" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_330_default" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_334"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_332" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_334" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_333"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_334" xlink:to="loc_us-gaap_SegmentDomain_333" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_333_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_334" xlink:to="loc_us-gaap_SegmentDomain_333_default" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FinitelivedIntangibleAssetsAcquired1" xlink:label="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_339"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_GoodwillAndOtherIntangibleAssetsLineItems_331" xlink:to="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_339" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_Goodwill" xlink:label="loc_us-gaap_Goodwill_336"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_GoodwillAndOtherIntangibleAssetsLineItems_331" xlink:to="loc_us-gaap_Goodwill_336" use="optional" order="10"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/GoodwillAndIntangibleAssetsSummaryOfIntangibleAssetsNetDetail">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_346"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_350"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_346" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_350" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsGross" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_349"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_346" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_349" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_348"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_346" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_348" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_345"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_348" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_345" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_347"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_345" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_347" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_347_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_345" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_347_default" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_PhysicianAndHospitalAgreementsMember" xlink:label="loc_md_PhysicianAndHospitalAgreementsMember_352"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_347" xlink:to="loc_md_PhysicianAndHospitalAgreementsMember_352" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_OtherTechnologyMember" xlink:label="loc_md_OtherTechnologyMember_813430"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_347" xlink:to="loc_md_OtherTechnologyMember_813430" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsNet" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsNet_351"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_346" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsNet_351" use="optional" order="9"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/DiscontinuedOperationsAdditionalInformationDetail">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_468359"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsGoodwillAndIntangibleAssets" xlink:label="loc_us-gaap_DeferredTaxAssetsGoodwillAndIntangibleAssets_413717"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_us-gaap_DeferredTaxAssetsGoodwillAndIntangibleAssets_413717" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AssetImpairmentCharges" xlink:label="loc_us-gaap_AssetImpairmentCharges_413567"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_us-gaap_AssetImpairmentCharges_413567" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_468356"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_us-gaap_StatementTable_468356" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_DeferredTaxAssetsAxis" xlink:label="loc_md_DeferredTaxAssetsAxis_468387"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_468356" xlink:to="loc_md_DeferredTaxAssetsAxis_468387" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_DeferredTaxAssetsDomain" xlink:label="loc_md_DeferredTaxAssetsDomain_468388"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_md_DeferredTaxAssetsAxis_468387" xlink:to="loc_md_DeferredTaxAssetsDomain_468388" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_DeferredTaxAssetsDomain" xlink:label="loc_md_DeferredTaxAssetsDomain_468388_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_md_DeferredTaxAssetsAxis_468387" xlink:to="loc_md_DeferredTaxAssetsDomain_468388_default" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_DeferredTaxAssetsIntangibleAssetsMember" xlink:label="loc_md_DeferredTaxAssetsIntangibleAssetsMember_468392"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_DeferredTaxAssetsDomain_468388" xlink:to="loc_md_DeferredTaxAssetsIntangibleAssetsMember_468392" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupClassificationAxis" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_813007"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_468356" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_813007" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_813008"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_813007" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_813008" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupClassificationDomain" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_813008_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_813007" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_813008_default" use="optional" order="10"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_NorthAmericanPartnersInAnesthesiaMember" xlink:label="loc_md_NorthAmericanPartnersInAnesthesiaMember_813010"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_813008" xlink:to="loc_md_NorthAmericanPartnersInAnesthesiaMember_813010" use="optional" order="11"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_DivestitureOfMeddataMember" xlink:label="loc_md_DivestitureOfMeddataMember_813021"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_813008" xlink:to="loc_md_DivestitureOfMeddataMember_813021" use="optional" order="12"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_RadiologyServicesMedicalGroupMember" xlink:label="loc_md_RadiologyServicesMedicalGroupMember_813022"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_813008" xlink:to="loc_md_RadiologyServicesMedicalGroupMember_813022" use="optional" order="13"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_AnesthesiologyServicesMedicalGroupMember" xlink:label="loc_md_AnesthesiologyServicesMedicalGroupMember_813661"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_813008" xlink:to="loc_md_AnesthesiologyServicesMedicalGroupMember_813661" use="optional" order="14"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_813013"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_468356" xlink:to="loc_srt_RangeAxis_813013" use="optional" order="15"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_813014"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_813013" xlink:to="loc_srt_RangeMember_813014" use="optional" order="16"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_813014_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_813013" xlink:to="loc_srt_RangeMember_813014_default" use="optional" order="17"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_813015"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_813014" xlink:to="loc_srt_MaximumMember_813015" use="optional" order="18"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_813016"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_813014" xlink:to="loc_srt_MinimumMember_813016" use="optional" order="19"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxPeriodAxis" xlink:label="loc_us-gaap_TaxPeriodAxis_813656"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_468356" xlink:to="loc_us-gaap_TaxPeriodAxis_813656" use="optional" order="20"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxPeriodDomain" xlink:label="loc_us-gaap_TaxPeriodDomain_813657"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TaxPeriodAxis_813656" xlink:to="loc_us-gaap_TaxPeriodDomain_813657" use="optional" order="21"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxPeriodDomain" xlink:label="loc_us-gaap_TaxPeriodDomain_813657_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TaxPeriodAxis_813656" xlink:to="loc_us-gaap_TaxPeriodDomain_813657_default" use="optional" order="22"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_TaxYearTwoThousandAndTwentyFiveMember" xlink:label="loc_md_TaxYearTwoThousandAndTwentyFiveMember_813658"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_813657" xlink:to="loc_md_TaxYearTwoThousandAndTwentyFiveMember_813658" use="optional" order="23"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_574665"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_574665" use="optional" order="24"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss_574666"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss_574666" use="optional" order="25"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal" xlink:label="loc_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal_574667"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal_574667" use="optional" order="26"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsFromDivestitureOfBusinesses" xlink:label="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_813004"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_us-gaap_ProceedsFromDivestitureOfBusinesses_813004" use="optional" order="27"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_MaximumConsiderationReceivable" xlink:label="loc_md_MaximumConsiderationReceivable_813005"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_md_MaximumConsiderationReceivable_813005" use="optional" order="28"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_Accountsreceivableretained" xlink:label="loc_md_Accountsreceivableretained_813006"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_md_Accountsreceivableretained_813006" use="optional" order="29"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_Capitallosscarryforward" xlink:label="loc_md_Capitallosscarryforward_813017"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_md_Capitallosscarryforward_813017" use="optional" order="30"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount" xlink:label="loc_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount_813018"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount_813018" use="optional" order="31"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_813019"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_813019" use="optional" order="32"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_DisposalGroupNotDiscontinuedOperationGoodwillImpairmentLoss" xlink:label="loc_md_DisposalGroupNotDiscontinuedOperationGoodwillImpairmentLoss_813020"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_md_DisposalGroupNotDiscontinuedOperationGoodwillImpairmentLoss_813020" use="optional" order="33"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RepaymentsOfLongTermDebtAndCapitalSecurities" xlink:label="loc_us-gaap_RepaymentsOfLongTermDebtAndCapitalSecurities_813023"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_us-gaap_RepaymentsOfLongTermDebtAndCapitalSecurities_813023" use="optional" order="34"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_813024"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_813024" use="optional" order="35"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity_813660"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity_813660" use="optional" order="36"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_PurchaseConsiderationCashPayment" xlink:label="loc_md_PurchaseConsiderationCashPayment_824842"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_md_PurchaseConsiderationCashPayment_824842" use="optional" order="37"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_NetProceedsForTheRadiologyServicesMedicalGroup" xlink:label="loc_md_NetProceedsForTheRadiologyServicesMedicalGroup_824843"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_468359" xlink:to="loc_md_NetProceedsForTheRadiologyServicesMedicalGroup_824843" use="optional" order="38"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/OperatingLeasesScheduleOfOperatingLeaseRelatedRightOfUseAssetsAndRelatedLiabilitiesRecordedOnTheCompanySBalanceSheetAndTheWeightedAverageRemainingLeaseTermAndDiscountRateDetails">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_393125"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_393122"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_393125" xlink:to="loc_us-gaap_StatementTable_393122" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_393123"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_393122" xlink:to="loc_us-gaap_StatementClassOfStockAxis_393123" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_393124"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_393123" xlink:to="loc_us-gaap_ClassOfStockDomain_393124" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_393124_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_393123" xlink:to="loc_us-gaap_ClassOfStockDomain_393124_default" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_OperatingLeasesAssetsAbstract" xlink:label="loc_md_OperatingLeasesAssetsAbstract_393127"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393125" xlink:to="loc_md_OperatingLeasesAssetsAbstract_393127" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseRightOfUseAsset" xlink:label="loc_us-gaap_OperatingLeaseRightOfUseAsset_393128"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_OperatingLeasesAssetsAbstract_393127" xlink:to="loc_us-gaap_OperatingLeaseRightOfUseAsset_393128" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_OperatingLeasesLiabilitiesAbstract" xlink:label="loc_md_OperatingLeasesLiabilitiesAbstract_393129"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393125" xlink:to="loc_md_OperatingLeasesLiabilitiesAbstract_393129" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_393130"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_OperatingLeasesLiabilitiesAbstract_393129" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_393130" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_393131"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_OperatingLeasesLiabilitiesAbstract_393129" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_393131" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_393133"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393125" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageDiscountRatePercent_393133" use="optional" order="10"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_OtherInformationRelatedToOperatingLeaseAbstract" xlink:label="loc_md_OtherInformationRelatedToOperatingLeaseAbstract_395101"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393125" xlink:to="loc_md_OtherInformationRelatedToOperatingLeaseAbstract_395101" use="optional" order="11"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1" xlink:label="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_393132"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_OtherInformationRelatedToOperatingLeaseAbstract_395101" xlink:to="loc_us-gaap_OperatingLeaseWeightedAverageRemainingLeaseTerm1_393132" use="optional" order="12"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/OperatingLeasesScheduleOfLeaseCostsForOperatingLeasesDetails">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_393157"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_393154"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_393157" xlink:to="loc_us-gaap_StatementTable_393154" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_393155"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_393154" xlink:to="loc_us-gaap_StatementClassOfStockAxis_393155" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_393156"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_393155" xlink:to="loc_us-gaap_ClassOfStockDomain_393156" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_393156_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_393155" xlink:to="loc_us-gaap_ClassOfStockDomain_393156_default" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseCost" xlink:label="loc_us-gaap_OperatingLeaseCost_393158"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393157" xlink:to="loc_us-gaap_OperatingLeaseCost_393158" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableLeaseCost" xlink:label="loc_us-gaap_VariableLeaseCost_393159"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393157" xlink:to="loc_us-gaap_VariableLeaseCost_393159" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_OperatingLeasesOtherCosts" xlink:label="loc_md_OperatingLeasesOtherCosts_393161"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393157" xlink:to="loc_md_OperatingLeasesOtherCosts_393161" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LeaseCost" xlink:label="loc_us-gaap_LeaseCost_393162"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393157" xlink:to="loc_us-gaap_LeaseCost_393162" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_OtherEquipmentRent" xlink:label="loc_md_OtherEquipmentRent_499989"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393157" xlink:to="loc_md_OtherEquipmentRent_499989" use="optional" order="9"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/OperatingLeasesScheduleOfSupplementalCashFlowInformationRelatedToOperatingLeasesDetails">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_393169"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_393166"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_393169" xlink:to="loc_us-gaap_StatementTable_393166" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_393167"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_393166" xlink:to="loc_us-gaap_StatementClassOfStockAxis_393167" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_393168"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_393167" xlink:to="loc_us-gaap_ClassOfStockDomain_393168" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_393168_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_393167" xlink:to="loc_us-gaap_ClassOfStockDomain_393168_default" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeasePayments" xlink:label="loc_us-gaap_OperatingLeasePayments_393170"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393169" xlink:to="loc_us-gaap_OperatingLeasePayments_393170" use="optional" order="5"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/OperatingLeasesScheduleOfOperatingLeaseLiabilitiesDetails">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementLineItems" xlink:label="loc_us-gaap_StatementLineItems_393177"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementTable" xlink:label="loc_us-gaap_StatementTable_393174"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_393177" xlink:to="loc_us-gaap_StatementTable_393174" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StatementClassOfStockAxis" xlink:label="loc_us-gaap_StatementClassOfStockAxis_393175"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_393174" xlink:to="loc_us-gaap_StatementClassOfStockAxis_393175" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_393176"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementClassOfStockAxis_393175" xlink:to="loc_us-gaap_ClassOfStockDomain_393176" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="loc_us-gaap_ClassOfStockDomain_393176_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementClassOfStockAxis_393175" xlink:to="loc_us-gaap_ClassOfStockDomain_393176_default" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_393179"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393177" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearTwo_393179" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_393180"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393177" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearThree_393180" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_393181"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393177" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_393181" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_393182"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393177" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_393182" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_393183"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393177" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueAfterYearFive_393183" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_393184"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393177" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDue_393184" use="optional" order="10"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiabilityCurrent" xlink:label="loc_us-gaap_OperatingLeaseLiabilityCurrent_393187"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393177" xlink:to="loc_us-gaap_OperatingLeaseLiabilityCurrent_393187" use="optional" order="11"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiabilityNoncurrent" xlink:label="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_393188"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393177" xlink:to="loc_us-gaap_OperatingLeaseLiabilityNoncurrent_393188" use="optional" order="12"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_413589"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393177" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityUndiscountedExcessAmount_413589" use="optional" order="13"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLeaseLiability" xlink:label="loc_us-gaap_OperatingLeaseLiability_413590"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393177" xlink:to="loc_us-gaap_OperatingLeaseLiability_413590" use="optional" order="14"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_555217"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_393177" xlink:to="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_555217" use="optional" order="15"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/LineOfCreditLongTermDebtAndFinanceLeaseObligationsAdditionalInformationDetail">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_396"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_416"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_416" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentDescriptionOfVariableRateBasis" xlink:label="loc_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_415"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_415" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentFaceAmount" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_418"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_418" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_DebtInstrumentMaturityYear" xlink:label="loc_md_DebtInstrumentMaturityYear_423"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_md_DebtInstrumentMaturityYear_423" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_419"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_419" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentMaturityDateDescription" xlink:label="loc_us-gaap_DebtInstrumentMaturityDateDescription_420"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_us-gaap_DebtInstrumentMaturityDateDescription_420" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed_421"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPricePercentageOfPrincipalAmountRedeemed_421" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LettersOfCreditOutstandingAmount" xlink:label="loc_us-gaap_LettersOfCreditOutstandingAmount_425"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_us-gaap_LettersOfCreditOutstandingAmount_425" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentRedemptionPricePercentage" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_422"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPricePercentage_422" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_413"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_413" use="optional" order="10"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_426"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_426" use="optional" order="11"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LineOfCreditFacilityTable" xlink:label="loc_us-gaap_LineOfCreditFacilityTable_400"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_us-gaap_LineOfCreditFacilityTable_400" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="12"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_393"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_400" xlink:to="loc_us-gaap_CreditFacilityAxis_393" use="optional" order="13"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_394"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_393" xlink:to="loc_us-gaap_CreditFacilityDomain_394" use="optional" order="14"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_394_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_393" xlink:to="loc_us-gaap_CreditFacilityDomain_394_default" use="optional" order="15"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_FivePointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentyThreeMember" xlink:label="loc_md_FivePointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentyThreeMember_411"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_394" xlink:to="loc_md_FivePointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentyThreeMember_411" use="optional" order="16"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LetterOfCreditMember" xlink:label="loc_us-gaap_LetterOfCreditMember_410"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_394" xlink:to="loc_us-gaap_LetterOfCreditMember_410" use="optional" order="17"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_SixPointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentySevenMember" xlink:label="loc_md_SixPointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentySevenMember_412"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_394" xlink:to="loc_md_SixPointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentySevenMember_412" use="optional" order="18"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_CreditAgreementMember" xlink:label="loc_md_CreditAgreementMember_812962"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_394" xlink:to="loc_md_CreditAgreementMember_812962" use="optional" order="19"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_UnsecuredRevolvingCreditFacilityMember" xlink:label="loc_md_UnsecuredRevolvingCreditFacilityMember_409"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_394" xlink:to="loc_md_UnsecuredRevolvingCreditFacilityMember_409" use="optional" order="20"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="loc_us-gaap_DebtInstrumentAxis_395"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_400" xlink:to="loc_us-gaap_DebtInstrumentAxis_395" use="optional" order="21"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_397"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_395" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_397" use="optional" order="22"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_397_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_395" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_397_default" use="optional" order="23"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_AlternateBaseRateMember" xlink:label="loc_md_AlternateBaseRateMember_427"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_397" xlink:to="loc_md_AlternateBaseRateMember_427" use="optional" order="24"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ApplicableMarginRateMember" xlink:label="loc_md_ApplicableMarginRateMember_428"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_397" xlink:to="loc_md_ApplicableMarginRateMember_428" use="optional" order="25"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodAxis" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_398"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_400" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_398" use="optional" order="26"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_399"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_398" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_399" use="optional" order="27"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodDomain" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_399_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodAxis_398" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_399_default" use="optional" order="28"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_DebtInstrumentRedemptionPeriodBeforeTwoThousandTwentyTwoMember" xlink:label="loc_md_DebtInstrumentRedemptionPeriodBeforeTwoThousandTwentyTwoMember_432"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_399" xlink:to="loc_md_DebtInstrumentRedemptionPeriodBeforeTwoThousandTwentyTwoMember_432" use="optional" order="29"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodFiveMember" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodFiveMember_435"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_399" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodFiveMember_435" use="optional" order="30"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodFourMember" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodFourMember_434"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_399" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodFourMember_434" use="optional" order="31"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_DebtInstrumentRedemptionPeriodSixAndThereafterMember" xlink:label="loc_md_DebtInstrumentRedemptionPeriodSixAndThereafterMember_436"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_399" xlink:to="loc_md_DebtInstrumentRedemptionPeriodSixAndThereafterMember_436" use="optional" order="32"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodThreeMember" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodThreeMember_433"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_399" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodThreeMember_433" use="optional" order="33"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentRedemptionPeriodTwoMember" xlink:label="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_430"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentRedemptionPeriodDomain_399" xlink:to="loc_us-gaap_DebtInstrumentRedemptionPeriodTwoMember_430" use="optional" order="34"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherOwnershipInterestsByNameAxis" xlink:label="loc_us-gaap_OtherOwnershipInterestsByNameAxis_401"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_400" xlink:to="loc_us-gaap_OtherOwnershipInterestsByNameAxis_401" use="optional" order="35"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherOwnershipInterestsNameDomain" xlink:label="loc_us-gaap_OtherOwnershipInterestsNameDomain_402"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_OtherOwnershipInterestsByNameAxis_401" xlink:to="loc_us-gaap_OtherOwnershipInterestsNameDomain_402" use="optional" order="36"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OtherOwnershipInterestsNameDomain" xlink:label="loc_us-gaap_OtherOwnershipInterestsNameDomain_402_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_OtherOwnershipInterestsByNameAxis_401" xlink:to="loc_us-gaap_OtherOwnershipInterestsNameDomain_402_default" use="optional" order="37"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ChangeInControlMember" xlink:label="loc_md_ChangeInControlMember_437"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherOwnershipInterestsNameDomain_402" xlink:to="loc_md_ChangeInControlMember_437" use="optional" order="38"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_403"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_400" xlink:to="loc_srt_RangeAxis_403" use="optional" order="39"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_404"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_403" xlink:to="loc_srt_RangeMember_404" use="optional" order="40"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_404_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_403" xlink:to="loc_srt_RangeMember_404_default" use="optional" order="41"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_439"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_404" xlink:to="loc_srt_MaximumMember_439" use="optional" order="42"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_438"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_404" xlink:to="loc_srt_MinimumMember_438" use="optional" order="43"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateAxis" xlink:label="loc_us-gaap_VariableRateAxis_407"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_400" xlink:to="loc_us-gaap_VariableRateAxis_407" use="optional" order="44"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_408"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_407" xlink:to="loc_us-gaap_VariableRateDomain_408" use="optional" order="45"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="loc_us-gaap_VariableRateDomain_408_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_407" xlink:to="loc_us-gaap_VariableRateDomain_408_default" use="optional" order="46"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FederalFundsEffectiveSwapRateMember" xlink:label="loc_us-gaap_FederalFundsEffectiveSwapRateMember_441"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_408" xlink:to="loc_us-gaap_FederalFundsEffectiveSwapRateMember_441" use="optional" order="47"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:label="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_442"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_408" xlink:to="loc_us-gaap_LondonInterbankOfferedRateLIBORMember_442" use="optional" order="48"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementScenarioAxis" xlink:label="loc_srt_StatementScenarioAxis_406"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LineOfCreditFacilityTable_400" xlink:to="loc_srt_StatementScenarioAxis_406" use="optional" order="49"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srt_ScenarioUnspecifiedDomain_405"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_406" xlink:to="loc_srt_ScenarioUnspecifiedDomain_405" use="optional" order="50"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srt_ScenarioUnspecifiedDomain_405_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_406" xlink:to="loc_srt_ScenarioUnspecifiedDomain_405_default" use="optional" order="51"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_RedeemUpToThirtyFivePercentageOfAggregatePrincipalAmountMember" xlink:label="loc_md_RedeemUpToThirtyFivePercentageOfAggregatePrincipalAmountMember_440"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_405" xlink:to="loc_md_RedeemUpToThirtyFivePercentageOfAggregatePrincipalAmountMember_440" use="optional" order="52"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ForecastForFirstQuarterOf2021Member" xlink:label="loc_md_ForecastForFirstQuarterOf2021Member_812965"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_405" xlink:to="loc_md_ForecastForFirstQuarterOf2021Member_812965" use="optional" order="53"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_ForecastForFourthQuarterOf2020Member" xlink:label="loc_md_ForecastForFourthQuarterOf2020Member_813365"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_405" xlink:to="loc_md_ForecastForFourthQuarterOf2020Member_813365" use="optional" order="54"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_424"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_us-gaap_LongTermDebt_424" use="optional" order="55"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_EstimatedEarningsBeforeInterestTaxesDepreciationAndAmortization" xlink:label="loc_md_EstimatedEarningsBeforeInterestTaxesDepreciationAndAmortization_812958"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_md_EstimatedEarningsBeforeInterestTaxesDepreciationAndAmortization_812958" use="optional" order="56"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_SupplementaryLeverageRatioRequired" xlink:label="loc_md_SupplementaryLeverageRatioRequired_812964"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_md_SupplementaryLeverageRatioRequired_812964" use="optional" order="57"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentPeriodicPaymentInterest" xlink:label="loc_us-gaap_DebtInstrumentPeriodicPaymentInterest_554301"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_396" xlink:to="loc_us-gaap_DebtInstrumentPeriodicPaymentInterest_554301" use="optional" order="58"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/LineOfCreditLongTermDebtAndFinanceLeaseObligationsScheduleOfLongTermDebtDetail">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_447"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_451"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_447" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_451" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="loc_us-gaap_DebtInstrumentTable_448"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_447" xlink:to="loc_us-gaap_DebtInstrumentTable_448" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_445"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_448" xlink:to="loc_us-gaap_CreditFacilityAxis_445" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_446"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_445" xlink:to="loc_us-gaap_CreditFacilityDomain_446" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_446_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_445" xlink:to="loc_us-gaap_CreditFacilityDomain_446_default" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_FivePointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentyThreeMember" xlink:label="loc_md_FivePointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentyThreeMember_449"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_446" xlink:to="loc_md_FivePointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentyThreeMember_449" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RevolvingCreditFacilityMember" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_450"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_446" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_450" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_LongTermDebtNet" xlink:label="loc_md_LongTermDebtNet_453"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_447" xlink:to="loc_md_LongTermDebtNet_453" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnamortizedDebtIssuanceExpense" xlink:label="loc_us-gaap_UnamortizedDebtIssuanceExpense_452"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_447" xlink:to="loc_us-gaap_UnamortizedDebtIssuanceExpense_452" use="optional" order="9"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/LineOfCreditLongTermDebtAndFinanceLeaseObligationsSummaryOfEstimatedFairValueOfNotesDetail">
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_DebtInstrumentFairValueLineItems" xlink:label="loc_md_DebtInstrumentFairValueLineItems_458"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_NotesPayableFairValueDisclosure" xlink:label="loc_us-gaap_NotesPayableFairValueDisclosure_466"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_DebtInstrumentFairValueLineItems_458" xlink:to="loc_us-gaap_NotesPayableFairValueDisclosure_466" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_DebtInstrumentFairValueTable" xlink:label="loc_md_DebtInstrumentFairValueTable_459"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_md_DebtInstrumentFairValueLineItems_458" xlink:to="loc_md_DebtInstrumentFairValueTable_459" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis" xlink:label="loc_us-gaap_FairValueByMeasurementBasisAxis_461"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_DebtInstrumentFairValueTable_459" xlink:to="loc_us-gaap_FairValueByMeasurementBasisAxis_461" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_555316"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_461" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_555316" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_555316_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByMeasurementBasisAxis_461" xlink:to="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_555316_default" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_555319"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PortionAtFairValueFairValueDisclosureMember_555316" xlink:to="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_555319" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="loc_us-gaap_CreditFacilityAxis_456"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_DebtInstrumentFairValueTable_459" xlink:to="loc_us-gaap_CreditFacilityAxis_456" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_457"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_456" xlink:to="loc_us-gaap_CreditFacilityDomain_457" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="loc_us-gaap_CreditFacilityDomain_457_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_456" xlink:to="loc_us-gaap_CreditFacilityDomain_457_default" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_SixPointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentySevenMember" xlink:label="loc_md_SixPointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentySevenMember_465"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_457" xlink:to="loc_md_SixPointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentySevenMember_465" use="optional" order="10"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_FivePointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentyThreeMember" xlink:label="loc_md_FivePointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentyThreeMember_464"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_457" xlink:to="loc_md_FivePointTwoFivePercentSeniorUnsecuredNotesDueTwoThousandTwentyThreeMember_464" use="optional" order="11"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_460"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_DebtInstrumentFairValueTable_459" xlink:to="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_460" use="optional" order="12"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_463"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_460" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_463" use="optional" order="13"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_463_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FairValueByFairValueHierarchyLevelAxis_460" xlink:to="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_463_default" use="optional" order="14"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_FairValueInputsLevel2Member" xlink:label="loc_us-gaap_FairValueInputsLevel2Member_469"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FairValueMeasurementsFairValueHierarchyDomain_463" xlink:to="loc_us-gaap_FairValueInputsLevel2Member_469" use="optional" order="15"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/IncomeTaxesAdditionalInformationDetail">
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_IncomeTaxLineItems" xlink:label="loc_md_IncomeTaxLineItems_493"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExaminationPenaltiesAndInterestAccrued" xlink:label="loc_us-gaap_IncomeTaxExaminationPenaltiesAndInterestAccrued_522"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_us-gaap_IncomeTaxExaminationPenaltiesAndInterestAccrued_522" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration_517"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsNotSubjectToExpiration_517" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration_516"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwardsSubjectToExpiration_516" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_505"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateContinuingOperations_505" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_NetOperatingLossCarryForwardsExpirationDate" xlink:label="loc_md_NetOperatingLossCarryForwardsExpirationDate_515"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_md_NetOperatingLossCarryForwardsExpirationDate_515" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OpenTaxYear" xlink:label="loc_us-gaap_OpenTaxYear_523"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_us-gaap_OpenTaxYear_523" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_OperatingLossCarryforwards" xlink:label="loc_us-gaap_OperatingLossCarryforwards_514"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_us-gaap_OperatingLossCarryforwards_514" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_IncomeTaxExpenseForExcessTaxDeficiencies" xlink:label="loc_md_IncomeTaxExpenseForExcessTaxDeficiencies_513"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_md_IncomeTaxExpenseForExcessTaxDeficiencies_513" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_IncomeTaxTable" xlink:label="loc_md_IncomeTaxTable_494"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_md_IncomeTaxTable_494" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ChangeInAccountingEstimateByTypeAxis" xlink:label="loc_us-gaap_ChangeInAccountingEstimateByTypeAxis_491"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_IncomeTaxTable_494" xlink:to="loc_us-gaap_ChangeInAccountingEstimateByTypeAxis_491" use="optional" order="10"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ChangeInAccountingEstimateTypeDomain" xlink:label="loc_us-gaap_ChangeInAccountingEstimateTypeDomain_492"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ChangeInAccountingEstimateByTypeAxis_491" xlink:to="loc_us-gaap_ChangeInAccountingEstimateTypeDomain_492" use="optional" order="11"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ChangeInAccountingEstimateTypeDomain" xlink:label="loc_us-gaap_ChangeInAccountingEstimateTypeDomain_492_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ChangeInAccountingEstimateByTypeAxis_491" xlink:to="loc_us-gaap_ChangeInAccountingEstimateTypeDomain_492_default" use="optional" order="12"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_495"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_IncomeTaxTable_494" xlink:to="loc_srt_RangeAxis_495" use="optional" order="13"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_496"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_495" xlink:to="loc_srt_RangeMember_496" use="optional" order="14"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_496_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_495" xlink:to="loc_srt_RangeMember_496_default" use="optional" order="15"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_525"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_496" xlink:to="loc_srt_MaximumMember_525" use="optional" order="16"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MinimumMember" xlink:label="loc_srt_MinimumMember_524"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_496" xlink:to="loc_srt_MinimumMember_524" use="optional" order="17"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_StatementScenarioAxis" xlink:label="loc_srt_StatementScenarioAxis_500"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_IncomeTaxTable_494" xlink:to="loc_srt_StatementScenarioAxis_500" use="optional" order="18"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srt_ScenarioUnspecifiedDomain_498"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementScenarioAxis_500" xlink:to="loc_srt_ScenarioUnspecifiedDomain_498" use="optional" order="19"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioUnspecifiedDomain" xlink:label="loc_srt_ScenarioUnspecifiedDomain_498_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementScenarioAxis_500" xlink:to="loc_srt_ScenarioUnspecifiedDomain_498_default" use="optional" order="20"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_ScenarioForecastMember" xlink:label="loc_srt_ScenarioForecastMember_526"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ScenarioUnspecifiedDomain_498" xlink:to="loc_srt_ScenarioForecastMember_526" use="optional" order="21"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ReasonablyPossibleSignificantChangeInUnrecognizedTaxBenefitsByItemAxis" xlink:label="loc_us-gaap_ReasonablyPossibleSignificantChangeInUnrecognizedTaxBenefitsByItemAxis_497"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_IncomeTaxTable_494" xlink:to="loc_us-gaap_ReasonablyPossibleSignificantChangeInUnrecognizedTaxBenefitsByItemAxis_497" use="optional" order="22"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleNatureOfUncertaintyDomain" xlink:label="loc_us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleNatureOfUncertaintyDomain_499"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ReasonablyPossibleSignificantChangeInUnrecognizedTaxBenefitsByItemAxis_497" xlink:to="loc_us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleNatureOfUncertaintyDomain_499" use="optional" order="23"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleNatureOfUncertaintyDomain" xlink:label="loc_us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleNatureOfUncertaintyDomain_499_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ReasonablyPossibleSignificantChangeInUnrecognizedTaxBenefitsByItemAxis_497" xlink:to="loc_us-gaap_SignificantChangeInUnrecognizedTaxBenefitsIsReasonablyPossibleNatureOfUncertaintyDomain_499_default" use="optional" order="24"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxPeriodAxis" xlink:label="loc_us-gaap_TaxPeriodAxis_501"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_IncomeTaxTable_494" xlink:to="loc_us-gaap_TaxPeriodAxis_501" use="optional" order="25"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxPeriodDomain" xlink:label="loc_us-gaap_TaxPeriodDomain_502"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TaxPeriodAxis_501" xlink:to="loc_us-gaap_TaxPeriodDomain_502" use="optional" order="26"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_TaxPeriodDomain" xlink:label="loc_us-gaap_TaxPeriodDomain_502_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TaxPeriodAxis_501" xlink:to="loc_us-gaap_TaxPeriodDomain_502_default" use="optional" order="27"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EarliestTaxYearMember" xlink:label="loc_us-gaap_EarliestTaxYearMember_528"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_502" xlink:to="loc_us-gaap_EarliestTaxYearMember_528" use="optional" order="28"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_LatestTaxYearMember" xlink:label="loc_us-gaap_LatestTaxYearMember_529"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TaxPeriodDomain_502" xlink:to="loc_us-gaap_LatestTaxYearMember_529" use="optional" order="29"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncreaseDecreaseInDeferredLiabilities" xlink:label="loc_us-gaap_IncreaseDecreaseInDeferredLiabilities_508"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_us-gaap_IncreaseDecreaseInDeferredLiabilities_508" use="optional" order="30"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:label="loc_us-gaap_DeferredTaxAssetsLiabilitiesNet_505887"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_us-gaap_DeferredTaxAssetsLiabilitiesNet_505887" use="optional" order="31"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnrecognizedTaxBenefits" xlink:label="loc_us-gaap_UnrecognizedTaxBenefits_518"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_us-gaap_UnrecognizedTaxBenefits_518" use="optional" order="32"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease_520"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsPeriodIncreaseDecrease_520" use="optional" order="33"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate_519"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsThatWouldImpactEffectiveTaxRate_519" use="optional" order="34"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_CapitalLossesIncurred" xlink:label="loc_md_CapitalLossesIncurred_583582"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_md_CapitalLossesIncurred_583582" use="optional" order="35"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_DeferredTaxLiabilities" xlink:label="loc_us-gaap_DeferredTaxLiabilities_597884"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_us-gaap_DeferredTaxLiabilities_597884" use="optional" order="36"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_CapitalLossCarryforwards" xlink:label="loc_md_CapitalLossCarryforwards_812993"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_md_CapitalLossCarryforwards_812993" use="optional" order="37"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_IncomeTaxExaminationPenaltiesAndInterestExpense" xlink:label="loc_us-gaap_IncomeTaxExaminationPenaltiesAndInterestExpense_812994"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_IncomeTaxLineItems_493" xlink:to="loc_us-gaap_IncomeTaxExaminationPenaltiesAndInterestExpense_812994" use="optional" order="38"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/StockIncentivePlansAndStockPurchasePlansAdditionalInformationDetail">
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AllocatedShareBasedCompensationExpense" xlink:label="loc_us-gaap_AllocatedShareBasedCompensationExpense_595"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_AllocatedShareBasedCompensationExpense_595" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockCapitalSharesReservedForFutureIssuance" xlink:label="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_594"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_CommonStockCapitalSharesReservedForFutureIssuance_594" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockSharesAuthorized" xlink:label="loc_us-gaap_CommonStockSharesAuthorized_592"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_CommonStockSharesAuthorized_592" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_598"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_598" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_599"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_599" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ProceedsAndExcessTaxBenefitFromSharebasedCompensation" xlink:label="loc_us-gaap_ProceedsAndExcessTaxBenefitFromSharebasedCompensation_602"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_ProceedsAndExcessTaxBenefitFromSharebasedCompensation_602" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_580"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_580" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_575"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_580" xlink:to="loc_us-gaap_AwardTypeAxis_575" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_582"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_575" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_582" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_582_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_575" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_582_default" use="optional" order="10"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeStockOptionMember" xlink:label="loc_us-gaap_EmployeeStockOptionMember_603"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_582" xlink:to="loc_us-gaap_EmployeeStockOptionMember_603" use="optional" order="11"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_RestrictedAndDeferredStockUnitsMember" xlink:label="loc_md_RestrictedAndDeferredStockUnitsMember_605"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_582" xlink:to="loc_md_RestrictedAndDeferredStockUnitsMember_605" use="optional" order="12"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="loc_us-gaap_RestrictedStockMember_604"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_582" xlink:to="loc_us-gaap_RestrictedStockMember_604" use="optional" order="13"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="loc_us-gaap_PlanNameAxis_576"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_580" xlink:to="loc_us-gaap_PlanNameAxis_576" use="optional" order="14"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_577"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_576" xlink:to="loc_us-gaap_PlanNameDomain_577" use="optional" order="15"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="loc_us-gaap_PlanNameDomain_577_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_576" xlink:to="loc_us-gaap_PlanNameDomain_577_default" use="optional" order="16"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_AmendedAndRestatedTwoThousandEightPlanMember" xlink:label="loc_md_AmendedAndRestatedTwoThousandEightPlanMember_585"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_577" xlink:to="loc_md_AmendedAndRestatedTwoThousandEightPlanMember_585" use="optional" order="17"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_NineteenNinetySixNonQualifiedEmployeeStockPurchasePlanAndTwoThousandFifteenNonQualifiedStockPurchasePlanMember" xlink:label="loc_md_NineteenNinetySixNonQualifiedEmployeeStockPurchasePlanAndTwoThousandFifteenNonQualifiedStockPurchasePlanMember_586"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_577" xlink:to="loc_md_NineteenNinetySixNonQualifiedEmployeeStockPurchasePlanAndTwoThousandFifteenNonQualifiedStockPurchasePlanMember_586" use="optional" order="18"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_NineteenNinetySixNonQualifiedEmployeeStockPurchasePlanMember" xlink:label="loc_md_NineteenNinetySixNonQualifiedEmployeeStockPurchasePlanMember_583"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_577" xlink:to="loc_md_NineteenNinetySixNonQualifiedEmployeeStockPurchasePlanMember_583" use="optional" order="19"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_TwoThousandFifteenNonQualifiedStockPurchasePlanMember" xlink:label="loc_md_TwoThousandFifteenNonQualifiedStockPurchasePlanMember_584"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_577" xlink:to="loc_md_TwoThousandFifteenNonQualifiedStockPurchasePlanMember_584" use="optional" order="20"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeAxis" xlink:label="loc_srt_RangeAxis_578"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_580" xlink:to="loc_srt_RangeAxis_578" use="optional" order="21"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_579"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_578" xlink:to="loc_srt_RangeMember_579" use="optional" order="22"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_RangeMember" xlink:label="loc_srt_RangeMember_579_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_578" xlink:to="loc_srt_RangeMember_579_default" use="optional" order="23"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2020/elts/srt-2020-01-31.xsd#srt_MaximumMember" xlink:label="loc_srt_MaximumMember_587"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_579" xlink:to="loc_srt_MaximumMember_587" use="optional" order="24"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_589"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_589" use="optional" order="25"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_597"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_597" use="optional" order="26"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_596"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_596" use="optional" order="27"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_590"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardExpirationPeriod_590" use="optional" order="28"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_588"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_588" use="optional" order="29"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_600"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_600" use="optional" order="30"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_591"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardPurchasePriceOfCommonStockPercent_591" use="optional" order="31"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_593"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans_593" use="optional" order="32"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_812976"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_812976" use="optional" order="33"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_812977"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate_812977" use="optional" order="34"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_812978"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_812978" use="optional" order="35"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_812980"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_581" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_812980" use="optional" order="36"/>
</definitionLink>
<definitionLink xlink:type="extended" xlink:role="http://www.mednax.com/role/CommonStockRepurchaseProgramsAdditionalInformationDetail">
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_CommonStockLineItems" xlink:label="loc_md_CommonStockLineItems_636"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_648"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_CommonStockLineItems_636" xlink:to="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_648" use="optional" order="1"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodShares" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_646"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_CommonStockLineItems_636" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_646" use="optional" order="2"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodValue" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue_645"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_CommonStockLineItems_636" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodValue_645" use="optional" order="3"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:label="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_643"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_CommonStockLineItems_636" xlink:to="loc_us-gaap_StockRepurchaseProgramAuthorizedAmount1_643" use="optional" order="4"/>
<loc xlink:type="locator" xlink:href="md-20201231.xsd#md_CommonStockTable" xlink:label="loc_md_CommonStockTable_637"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_md_CommonStockLineItems_636" xlink:to="loc_md_CommonStockTable_637" xbrldt:contextElement="segment" xbrldt:closed="true" use="optional" order="5"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="loc_us-gaap_AwardTypeAxis_635"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_CommonStockTable_637" xlink:to="loc_us-gaap_AwardTypeAxis_635" use="optional" order="6"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_639"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_635" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_639" use="optional" order="7"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_639_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_635" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_639_default" use="optional" order="8"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_RestrictedStockMember" xlink:label="loc_us-gaap_RestrictedStockMember_650"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_639" xlink:to="loc_us-gaap_RestrictedStockMember_650" use="optional" order="9"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramAxis" xlink:label="loc_us-gaap_ShareRepurchaseProgramAxis_640"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_CommonStockTable_637" xlink:to="loc_us-gaap_ShareRepurchaseProgramAxis_640" use="optional" order="10"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_641"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_640" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_641" use="optional" order="11"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_ShareRepurchaseProgramDomain" xlink:label="loc_us-gaap_ShareRepurchaseProgramDomain_641_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareRepurchaseProgramAxis_640" xlink:to="loc_us-gaap_ShareRepurchaseProgramDomain_641_default" use="optional" order="12"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CollateralAxis" xlink:label="loc_us-gaap_CollateralAxis_642"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_CommonStockTable_637" xlink:to="loc_us-gaap_CollateralAxis_642" use="optional" order="13"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CollateralDomain" xlink:label="loc_us-gaap_CollateralDomain_638"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CollateralAxis_642" xlink:to="loc_us-gaap_CollateralDomain_638" use="optional" order="14"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CollateralDomain" xlink:label="loc_us-gaap_CollateralDomain_638_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CollateralAxis_642" xlink:to="loc_us-gaap_CollateralDomain_638_default" use="optional" order="15"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_CommonStockMember" xlink:label="loc_us-gaap_CommonStockMember_824954"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CollateralDomain_638" xlink:to="loc_us-gaap_CommonStockMember_824954" use="optional" order="16"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="loc_us-gaap_SubsequentEventTypeAxis_412583"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_md_CommonStockTable_637" xlink:to="loc_us-gaap_SubsequentEventTypeAxis_412583" use="optional" order="17"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_412584"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_412583" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_412584" use="optional" order="18"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="loc_us-gaap_SubsequentEventTypeDomain_412584_default"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_SubsequentEventTypeAxis_412583" xlink:to="loc_us-gaap_SubsequentEventTypeDomain_412584_default" use="optional" order="19"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation" xlink:label="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_647"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_CommonStockLineItems_636" xlink:to="loc_us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation_647" use="optional" order="20"/>
<loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2020/elts/us-gaap-2020-01-31.xsd#us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1" xlink:label="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_554331"/>
<definitionArc xlink:type="arc" xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_md_CommonStockLineItems_636" xlink:to="loc_us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1_554331" use="optional" order="21"/>
</definitionLink>
</linkbase>

3 Subsequent Filings that Reference this Filing

  As Of               Filer                 Filing    For·On·As Docs:Size             Issuer                      Filing Agent

 2/20/24  Pediatrix Medical Group, Inc.     10-K       12/31/23   99:12M                                    Donnelley … Solutions/FA
 2/17/23  Pediatrix Medical Group, Inc.     10-K       12/31/22   97:14M                                    Donnelley … Solutions/FA
 2/17/22  Pediatrix Medical Group, Inc.     10-K       12/31/21   96:13M                                    Donnelley … Solutions/FA

25 Previous Filings that this Filing References

  As Of               Filer                 Filing    For·On·As Docs:Size             Issuer                      Filing Agent

11/06/20  Pediatrix Medical Group, Inc.     10-Q        9/30/20   57:5.3M                                   Donnelley … Solutions/FA
 9/15/20  Pediatrix Medical Group, Inc.     8-K:1,5,9   9/09/20   11:931K                                   Donnelley … Solutions/FA
 7/30/20  Pediatrix Medical Group, Inc.     10-Q        6/30/20   55:4.5M                                   Donnelley … Solutions/FA
 7/13/20  Pediatrix Medical Group, Inc.     8-K:1,5,7,9 7/12/20   15:570K                                   Donnelley … Solutions/FA
 5/12/20  Pediatrix Medical Group, Inc.     8-K:1,2,9   5/06/20   12:949K                                   Donnelley … Solutions/FA
 5/07/20  Pediatrix Medical Group, Inc.     10-Q        3/31/20   57:5.4M                                   Donnelley … Solutions/FA
 4/28/20  Pediatrix Medical Group, Inc.     10-K/A     12/31/19   19:2.5M                                   Donnelley … Solutions/FA
 2/20/20  Pediatrix Medical Group, Inc.     10-K       12/31/19   97:13M                                    Donnelley … Solutions/FA
10/10/19  Pediatrix Medical Group, Inc.     8-K:1,7,9  10/10/19   12:746K                                   Donnelley … Solutions/FA
 5/02/19  Pediatrix Medical Group, Inc.     10-Q        3/31/19   62:4.4M                                   Donnelley … Solutions/FA
 3/29/19  Pediatrix Medical Group, Inc.     DEF 14A     5/16/19    2:2.4M                                   Donnelley … Solutions/FA
 2/14/19  Pediatrix Medical Group, Inc.     10-K       12/31/18   92:7.4M                                   Donnelley … Solutions/FA
11/13/18  Pediatrix Medical Group, Inc.     8-K:1,2,9  11/13/18    2:538K                                   Donnelley … Solutions/FA
11/06/18  Pediatrix Medical Group, Inc.     8-K:5,9    11/06/18    2:122K                                   Donnelley … Solutions/FA
 2/14/18  Pediatrix Medical Group, Inc.     10-K       12/31/17   95:6.7M                                   Donnelley … Solutions/FA
11/01/17  Pediatrix Medical Group, Inc.     10-Q        9/30/17   52:3M                                     Donnelley … Solutions/FA
12/08/15  Pediatrix Medical Group, Inc.     8-K:1,2,9  12/08/15    3:983K                                   Donnelley … Solutions/FA
 9/18/15  Pediatrix Medical Group, Inc.     DEF 14A    11/03/15    1:1.4M                                   Donnelley … Solutions/FA
 2/12/14  Pediatrix Medical Group, Inc.     10-K       12/31/13   90:6.9M                                   Donnelley … Solutions/FA
 2/29/12  Pediatrix Medical Group, Inc.     10-K       12/31/11   88:7.3M                                   Donnelley … Solutions/FA
 2/27/09  Pediatrix Medical Group, Inc.     10-K       12/31/08    8:1.2M                                   Donnelley … Solutions/FA
 1/02/09  Pediatrix Medical Group, Inc.     8-K12B:1,3,12/29/08   17:783K                                   Donnelley … Solutions/FA
12/10/04  Pediatrix Medical Group, Inc.     S-8        12/10/04    4:265K                                   Bowne of Atlanta Inc./FA
11/15/02  Pediatrix Medical Group, Inc.     S-8        11/15/02    3:252K                                   Bowne of Atlanta Inc./FA
 8/13/98  Pediatrix Medical Group, Inc.     10-Q        6/30/98    6:84K                                    Global Fin’l Press/FL/FA
↑Top
Filing Submission 0001193125-21-047064   –   Alternative Formats (Word / Rich Text, HTML, Plain Text, et al.)
Copyright © 2024 Fran Finnegan & Company LLC – All Rights Reserved.
About — Privacy — Redactions — Help — Fri., May 17, 1:15:20.3pm ET