Buprenorphine Treatment in Pregnancy and Maternal-Infant Outcomes.

Importance: Opioid use disorder (OUD) in pregnancy has grown in the US. Buprenorphine, a medication to treat OUD, may improve pregnancy outcomes; however, most pregnant individuals do not receive it. Research evaluating buprenorphine use in pregnancy, its effects on the maternal-infant dyad, and in comparison to no treatment is limited. Objective: To determine if treatment with buprenorphine for opioid use disorder in pregnancy is associated with improved maternal and infant outcomes compared to no treatment among mothers with OUD. Design, Setting, and Participants: This retrospective cohort study included maternal-infant dyads continuously enrolled in the Tennessee Medicaid program from 20 weeks' estimated gestational age to 6 weeks post partum between 2010 and 2021. Medicaid administrative was linked to birth and death certificates. Data analysis was conducted from April to October 2024. Exposure: Buprenorphine use during pregnancy. Main Outcomes and Measures: Adverse pregnancy outcomes included preterm birth, neonatal intensive care unit (NICU) admission, infant death, severe maternal morbidity (SMM), intensive care unit admission, and maternal death. Logistic regression and propensity scores with overlap weighting were used to calculate adjusted predicted probabilities for adverse outcomes. Results: Among 14 463 maternal-infant dyads, 7469 (51.6%) received buprenorphine treatment (median [IQR] maternal age, 27 [24-31] years). There was a statistically significant lower rate of adverse pregnancy outcomes among dyads treated with buprenorphine compared to untreated dyads (25.4% vs 30.8%; P < .001); the treatment group also had a lower rate of SMM events (5.4% vs 6.9%; P < .001), preterm births (14.1% vs 20.0%; P < .001), and NICU admissions (15.2% vs 17.2%; P = .001). In adjusted analyses, those with buprenorphine treatment had a 5.1 percentage point (pp; 95% CI, 3.5-6.7 pp) lower probability of any adverse outcomes, including a 1.2 pp (95% CI, 0.4-2.1 pp) lower probability of SMM, 1.7 pp (95% CI, 0.4-2.9 pp) lower probability of NICU admission, and 5.3 pp (95% CI, 4.0-6.6 pp) lower probability of preterm birth. The number needed to treat to avoid an adverse pregnancy outcome was 20. Conclusions and Relevance: In this cohort study of pregnant individuals with OUD, buprenorphine treatment was associated with improved outcomes for the mother and infant, underscoring the need to improve access to treatment nationwide.