(P-538) Pregnancy and Neonatal Outcomes Associated with Opioid Assisted Treatments and Unexposed Pregnancies

Background: Adverse pregnancy and neonatal outcomes associated with opioid assisted treatment (OAT) using buprenorphine, methadone, or unexposed pregnancies are underinvestigated.

Objectives: To quantify the association of adverse pregnancy and neonatal outcomes and prenatal exposure to OAT using buprenorphine, methadone, or no OAT exposure and evaluate any impact of timing of prenatal exposure.

Methods: We conducted a retrospective cohort study of eligible mother-infant dyads with opioid use disorder, using the Rhode Island Medicaid claims data linked to birth certificates 2008-2016. To assess the risk of adverse pregnancy and neonatal outcomes with prenatal exposure to buprenorphine, methadone, and no OAT exposure, we applied Marginal Structural Models (MSMs) with two time periods (before and after 20 weeks of gestation) that accounted for time-varying exposure and covariates (e.g., concomitant medication use). We estimated adjusted odds ratios (aORs) and 95% confidence intervals using MSMs.

Results: Of 406 eligible pregnancies, 146 (40.0%) remained unexposed throughout pregnancy, 98 (24.1%) and 76 (18.7%) were exposed to buprenorphine and 136 (42.4%) and 152 (37.4%) were exposed to methadone early and late in pregnancy, respectively. Compared to prenatal buprenorphine exposure both early and late in pregnancy, prenatal methadone exposure was associated with increased risk of preterm birth (PTB) (aOR: 14.31[3.49-58.71]), low birth weight (LBW) (aOR: 7.81[2.31-26.32]), neonatal abstinence syndrome (NAS) (aOR, 2.31[1.07-4.97]), neonatal intensive care unit admission (NICUa) (aOR, 3.07[1.43-6.59]), and maternal hospital stay (>7 days) (aOR: 3.29[1.51-7.19]). Compared to unexposed pregnancies, prenatal methadone exposure late or both early and late in pregnancy was associated with increased risk of PTB (aOR, 5.08[1.80-14.36]; 4.16[1.17-14.79]), NICUa (aOR, 5.18[2.20-12.18]; 3.85[1.66-8.95]), NAS (aOR, 11.69[4.32-31.65]; 9.09[3.38-24.47]), and respiratory symptoms (aOR, 3.38 [1.19-9.57]; 3.76[1.37-10.34]). Prenatal buprenorphine exposure late or both early and late in pregnancy was associated with a higher risk of NAS (aOR: 5.06[1.50-17.10]; 3.94[1.48-10.51]) than unexposed, while buprenorphine exposure early and late in pregnancy was associated with a lower risk of LBW (aOR: 0.29[0.09-0.96]).

Conclusions: We did not observe differences in the risk of adverse neonatal outcomes associated with early pregnancy OAT exposures. Prenatal methadone exposure late or both early and late in pregnancy was associated with a higher risk of adverse neonatal outcomes compared with prenatal buprenorphine exposure or unexposed.