Medicaid expansion in Oregon and postpartum healthcare among people with and without prenatal substance use disorder

•Associations between Medicaid expansion and Medicaid-financed postpartum healthcare differed by SUD.•Medicaid expansion not associated with increased Medicaid-financed postpartum care in people with SUD.•Medicaid expansion associated with increased Medicaid-financed postpartum care in people without SUD.•For OUD, Medicaid expansion associated with increased Medicaid-financed OUD-related medications.