Association of Expanded Prenatal Care Coverage for Immigrant Women With Postpartum Contraception and Short Interpregnancy Interval Births

IMPORTANCE: Access to prenatal and postpartum care is restricted among women with low income who are recent or undocumented immigrants enrolled in Emergency Medicaid. OBJECTIVE: To examine the association of extending prenatal care coverage to Emergency Medicaid enrollees with postpartum contraception and short interpregnancy interval births. DESIGN, SETTING, AND PARTICIPANTS: This cohort study used a difference-in-differences design to compare the staggered rollout of prenatal care in Oregon with South Carolina, a state that does not cover prenatal or postpartum care. Linked Medicaid claims and birth certificate data from 2010 to 2016 were examined for an association between prenatal care coverage for women whose births were covered by Emergency Medicaid and subsequent short IPI births. Additional maternal and infant health outcomes were also examined, including postpartum contraceptive use, preterm birth, and neonatal intensive care unit admission. The association between the policy change and measures of policy implementation (number of prenatal visits) and quality of care (receipt of 8 guideline-based screenings) was also analyzed. Statistical analysis was performed from August 2020 to March 2021. EXPOSURES: Medicaid coverage of prenatal care. MAIN OUTCOMES AND MEASURES: Postpartum contraceptive use, defined as receipt of any contraceptive method within 60 days of delivery; short IPI births, defined as occurring within 18 months of a previous pregnancy. RESULTS: The study population consisted of 26 586 births to women enrolled in Emergency Medicaid in Oregon and South Carolina. Among these women, 14 749 (55.5%) were aged 25 to 35 years, 25 894 (97.4%) were Black, Hispanic, Native American, Alaskan, Pacific Islander, or Asian women or women with unknown race/ethnicity, and 17 905 (67.3%) lived in areas with urban zip codes. Coverage of prenatal care for women in Emergency Medicaid was associated with significant increases in mean (SD) prenatal visits (increase of 10.3 [0.9] prenatal visits) and prenatal quality. Prenatal care screenings (eg, anemia screening: increase of 65.7 percentage points [95% CI, 54.2 to 77.1 percentage points]) and vaccinations (eg, influenza vaccination: increase of 31.9 percentage points [95% CI, 27.4 to 36.3 percentage points]) increased significantly following the policy change. Although postpartum contraceptive use increased following prenatal care expansion (increase of 1.5 percentage points [95% CI, 0.4 to 2.6 percentage points]), the policy change was not associated with a reduction in short IPI births (−4.5 percentage points [95% CI, −9.5 to 0.5 percentage points), preterm births (−0.6 percentage points [95% CI, –3.2 to 2.0 percentage points]), or neonatal intensive care unit admissions (increase of 0.8 percentage points [95% CI, −2.0 to 3.6 percentage points]). CONCLUSIONS AND RELEVANCE: This study found that expanding Emergency Medicaid benefits to include prenatal care significantly improved receipt of guideline-concordant prenatal care. Prenatal care coverage alone was not associated with a meaningful increase in postpartum contraception or a reduction in subsequent short IPI births.