Background: Lack of quality preventive care has been associated with poorer outcomes for pregnant women with low incomes. Health policy changes implemented with the Affordable Care Act (ACA) were designed to improve access to care. However, insurance coverage remains lower among women in Medicaid nonexpansion states. We compared health care use and adverse birth outcomes by insurance status among women giving birth in a large health system in a Medicaid nonexpansion state.

Materials and Methods: We conducted a population-based retrospective cohort study using data for 9,613 women with deliveries during 2014–2015 at six hospitals associated with a large vertically integrated health care system in North Carolina. Adjusted logistic regression and zero-inflated negative binomial models examined associations between insurance status at delivery (commercial, Medicaid, or uninsured) and health care utilization (well-woman visits, late prenatal care, adequacy of prenatal care, postpartum follow-up, and emergency department [ED] visits) and outcomes (preterm birth, low birth weight, preeclampsia, and gestational diabetes).

Results: Having Medicaid at delivery was associated with lower rates of well-woman visits (rate ratio [RR] 0.25, 95% CI 0.23–0.28), higher rates of ED visits (RR 2.93, 95% CI 2.64–3.25), and higher odds of late prenatal care (odds ratio [OR] 1.18, 95% CI 1.03–1.34) compared to having commercial insurance, with similar results for uninsured women. Differences in adverse pregnancy outcomes were not statistically significant after adjusting for patient characteristics.

Conclusions: Findings suggest that large gaps exist in use of preventive care between Medicaid/uninsured and commercially insured women. Policymakers should consider ways to improve potential and realized access to care.