Neonatal Outcomes Better With Buprenorphine in Pregnant Women With Opioid Use Disorder

The risk of adverse neonatal outcomes was lower in pregnant women with opioid use disorder treated with buprenorphine than methadone, according to a study published in The New England Journal of Medicine.

“In this cohort study that drew from a large database of Medicaid beneficiaries, we observed strong inverse associations between buprenorphine use in pregnancy (as compared with methadone use) and neonatal abstinence syndrome, preterm birth, small size for gestational age, and low birth weight,” wrote corresponding author Elizabeth A. Suarez, PhD, MPH, of Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts, and study coauthors. “Adjustment for an extensive list of measured confounders did not meaningfully change the estimates.”

The study included 10,704 women exposed to buprenorphine and 4387 women exposed to methadone in early pregnancy, and 11,272 exposed to buprenorphine and 5056 exposed to methadone in late pregnancy (gestational week 20 through the day before delivery).

Among 9976 women exposed to buprenorphine and 4597 to methadone in the 30 days before delivery, rates of neonatal abstinence syndrome were 52% with buprenorphine and 69.2% with methadone, resulting in an adjusted relative risk of 0.73, according to the study.

With early pregnancy exposure, rates of preterm birth were 14.4% with buprenorphine and 24.9% with methadone (0.58 adjusted relative risk); small size for gestational age, 12.1% with buprenorphine and 15.3% with methadone (0.72 adjusted relative risk); and low birth weight, 8.3% with buprenorphine and 14.9% with methadone (0.56 adjusted relative risk), researchers reported.

Adverse maternal outcomes with early exposure were comparable between treatments, the study found. Cesarean section rates were 33.6% with buprenorphine and 33.1% with methadone, and rates of severe maternal complications were 3.3% with buprenorphine and 3.5% with methadone.

Exposure in late pregnancy, researchers noted, was associated with similar results.

Reference

Suarez EA, Huybrechts KF, Straub L, et al. Buprenorphine versus methadone for opioid use disorder in pregnancy. N Engl J Med. 2022;387(22):2033-2044. doi:10.1056/NEJMoa2203318