Medicaid Expansion and Severe Maternal Morbidity

OBJECTIVE: To evaluate whether there is an association between state-level Medicaid expansion and severe maternal morbidity (SMM) among Medicaid enrollees who delivered between 2010 and 2018. METHODS: This is a secondary analysis of Medicaid claims that uses national Medicaid analytic files. We included Medicaid enrollees with delivery hospitalizations between 2010 and 2018 in all states that expanded Medicaid under the Affordable Care Act (ACA) by July 2016. The primary outcome was SMM, defined using the Centers for Disease Control and Prevention's validated list of 21 indicators. The primary exposure was whether the enrollee's state of residence had expanded Medicaid 21 months before their delivery under the ACA, to allow for 1 year of expansion before a 9-month pregnancy. We also included analyses that allowed for a 9-month lag after expansion so that Medicaid expansion was in place at the start of a pregnancy. We calculated annual rates of SMM by Medicaid expansion status and analyzed trends across time. We used logistic regression to estimate the association between timing of deliveries relative to Medicaid expansion and SMM at the delivery encounter. RESULTS: Data for 6,976,586 individuals were available for analysis in 30 of the 31 states that expanded Medicaid by July 2016. Rates of SMM trended downward after Medicaid expansion in these states. Individuals who delivered at least 21 months after state Medicaid expansions were significantly less likely to experience SMM relative to those who delivered before Medicaid expansion (including blood transfusion: odds ratio [OR] 0.79; 95% CI, 0.68–0.90; excluding blood transfusion: OR 0.76; 95% CI, 0.65–0.88). CONCLUSION: Medicaid expansion was associated with decreased odds of SMM.