Association of Medicaid vs Marketplace Eligibility on Maternal Coverage and Access With Prenatal and Postpartum Care

IMPORTANCE: Policy makers are considering insurance expansions to improve maternal health. The tradeoffs between expanding Medicaid or subsidized private insurance for maternal coverage and care are unknown. OBJECTIVE: To compare maternal coverage and care by Medicaid vs marketplace eligibility. DESIGN, SETTING, AND PARTICIPANTS: A retrospective cohort study using a difference-in-difference research design was conducted from March 14, 2020, to April 22, 2021. Maternal coverage and care use were compared among women with family incomes 100% to 138% of the federal poverty level (FPL) residing in 10 Medicaid expansion sites (exposure group) who gained Medicaid eligibility under the Affordable Care Act and in 5 nonexpansion sites (comparison group) who gained marketplace eligibility before (2011-2013) and after (2015-2018) insurance expansion implementation. Participants included women aged 18 years or older from the 2011-2018 Pregnancy Risk Assessment Monitoring System survey. EXPOSURES: Eligibility for Medicaid or marketplace coverage under the Affordable Care Act. MAIN OUTCOMES AND MEASURES: Outcomes included coverage in the preconception and postpartum periods, early and adequate prenatal care, and postpartum checkups and effective contraceptive use. RESULTS: The study population included 11 432 women age 18 years and older (32% age 18-24 years, 33% age 25-29 years, 35% age ≥30 years) with incomes 100% to 138% FPL: 7586 in a Medicaid state (exposure group) and 3846 in a nonexpansion marketplace state (comparison group). Women in marketplace states were younger, had higher educational level and marriage rates, and had less racial and ethnic diversity. Medicaid relative to marketplace eligibility was associated with increased Medicaid coverage (20.3 percentage points; 95% CI, 12.8 to 30.0 percentage points), decreased private insurance coverage (−10.8 percentage points; 95% CI, −13.3 to −7.5 percentage points), and decreased uninsurance (−8.7 percentage points; 95% CI, −20.1 to −0.1 percentage points) in the preconception period, increased postpartum Medicaid (17.4 percentage points; 95% CI, 1.7 to 34.3 percentage points) and increased adequate prenatal care (4.4 percentage points; 95% CI, 0.1 to 11.0 percentage points) in difference-in-difference models. No evidence of significant differences in early prenatal care, postpartum check-ups, or postpartum contraception was identified. CONCLUSIONS AND RELEVANCE: In this cohort study, eligibility for Medicaid was associated with increased Medicaid, lower preconception uninsurance, and increased adequate prenatal care use. The lower rates of preconception uninsurance among Medicaid-eligible women suggest that women with low incomes were facing barriers to marketplace enrollment, underscoring the potential importance of reducing financial barriers for the population with low incomes.