ACA Medicaid Expansion and Insurance Coverage Among New Mothers Living in Poverty.

BACKGROUND: Medicaid plays a critical role during the perinatal period, but pregnancy-related Medicaid eligibility only extends for 60 days post partum. In 2014, the Affordable Care Act's (ACA's) Medicaid expansions increased adult Medicaid eligibility to 138% of the federal poverty level in participating states, allowing eligible new mothers to remain covered after pregnancy-related coverage expires. We investigate the impact of ACA Medicaid expansions on insurance coverage among new mothers living in poverty. METHODS: We define new mothers living in poverty as women ages 19 to 44 with incomes below the federal poverty level who report giving birth in the past 12 months. We use 2010-2017 American Community Survey data and a difference-in-differences approach using parental Medicaid-eligibility thresholds to estimate the effect of ACA Medicaid expansions on insurance coverage among poor new mothers. RESULTS: A 100-percentage-point increase in parental Medicaid-eligibility is associated with an 8.8-percentage-point decrease (P < .001) in uninsurance, a 13.2-percentage-point increase (P < .001) in Medicaid coverage, and a 4.4-percentage-point decrease in private or other coverage (P = .001) among poor new mothers. The average increase in Medicaid eligibility is associated with a 28% decrease in uninsurance, a 13% increase in Medicaid coverage, and an 18% decline in private or other insurance among poor new mothers in expansion states. However, in 2017, there were ∼142 000 remaining uninsured, poor new mothers. CONCLUSIONS: ACA Medicaid expansions are associated with increased Medicaid coverage and reduced uninsurance among poor new mothers. Opportunities remain for expansion and nonexpansion states to increase insurance coverage among new mothers living in poverty.