Association of Prenatal Care Expansion With Use of Antidiabetic Agents During Pregnancies Among Latina Emergency Medicaid Recipients With Gestational Diabetes

IMPORTANCE: Access to necessary prenatal care is not guaranteed through Medicaid for some people with low income based on their immigration status. Although states have the option to extend emergency Medicaid coverage for prenatal care, many states have not expanded coverage. OBJECTIVE: To evaluate whether the receipt of prenatal care services through the extension of emergency Medicaid coverage is associated with an increase in antidiabetic medication use among Latina patients with gestational diabetes. DESIGN, SETTING, AND PARTICIPANTS: This cohort study used linked Medicaid claims and birth certificate data on live births to 4869 Latina patients from October 1, 2010, to December 31, 2019, with a difference-in-differences design to compare the rollout of prenatal care and services in Oregon in 2013 with a comparison state, South Carolina, that did not cover prenatal or postpartum care. EXPOSURE: Medicaid coverage of prenatal care. MAIN OUTCOMES AND MEASURES: The main outcome was the receipt of antidiabetic agents. Secondary outcomes included hypertensive disorders, cesarean delivery, postpartum contraception, and a newborn morbidity composite outcome (large size for gestational age, neonatal intensive care unit admission, and preterm birth). RESULTS: The study sample included live births to 4869 Latina patients (mean [SD] age, 32.7 [5.5] years [range, 12-44 years]) enrolled in emergency Medicaid who were mainly aged 25 to 34 years (1499 of 2907 [51.6%]), multiparous (2626 of 2907 [90.3%]), and living in urban areas (2299 of 2907 [79.1%]). After Oregon’s policy change to offer prenatal coverage to individuals receiving emergency Medicaid, there was a large and significant increase in the receipt of antidiabetic agents among all people with diabetes during pregnancy (gestational diabetes). Prior to the policy, only 0.3% of all Latina emergency Medicaid recipients with gestational diabetes (2 of 617) received any medication (oral agents or insulin) to manage their blood glucose level. After the policy change, 28.8% of all patients with gestational diabetes (295 of 1023) received medication to manage their blood glucose level, translating to a 27.9-percentage-point increase (95% CI, 24.5-31.2 percentage points) in the receipt of antidiabetic agents in the adjusted model. The policy was also associated with a 10.4-percentage-point (95% CI, 5.3-15.5 percentage points) increase in insulin use during pregnancy among all patients with gestational diabetes. We observed an increase in postpartum contraceptive use (21.2 percentage points; 95% CI, 14.9-27.5 percentage points), the majority of which was due to postpartum sterilization (increase of 16.1 percentage points; 95% CI, 10.4-21.8 percentage points). We did not observe a significant association with gestational hypertension, cesarean births, or newborn health. CONCLUSIONS AND RELEVANCE: This retrospective cohort study suggests that expanded emergency Medicaid benefits that included prenatal care were associated with an increased use of antidiabetic medications and postpartum contraception during pregnancy.