Buprenorphine Reduces Risk of Adverse Neonatal Outcomes

Pregnant individuals with opioid use disorder are commonly treated with methadone.

Pregnant individuals with opioid use disorder (OUD) treated with buprenorphine have more favorable outcomes than those treated with methadone.

A team, led by Elizabeth A. Suarez, PhD, compared the 2 treatments in a large cohort of pregnant individuals.

Standard Care

Standard care regimens for pregnant individuals with opioid use disorder includes opioid agonist therapy, including buprenorphine, which may be associated with more favorable neonatal and maternal outcomes compared to methadone.

However, the data comparing the 2 treatments is limited in this patient population.

In the cohort study, the investigators examined data on pregnant individuals enrolled in public insurance programs in the US between 2000-2018. The team looked at outcomes among patients treated with buprenorphine compared to those who were treated with methadone.

The investigators assessed exposure to the 2 medications in early pregnancy, defined as through gestational week 19, later pregnancy, defined as gestational week 20 through the day before delivery, and the 30 days prior to delivery.

They also adjusted risk ratios for neonatal and maternal outcomes for confounders with the use of propensity-score overlap weights.

Overall, the team analyzed data from 2.5 million pregnancies that ended in live births. A total of 10,704 of pregnant participants were exposed to buprenorphine in early pregnancy, compared to 4387 individuals exposed to methadone.

In late pregnancy, 11,272 individuals were exposed to buprenorphine, compared to 5056 individuals exposed to methadone (9976 and 4597, respectively, in the 30 days before delivery).

Birth Outcomes

In addition, 52% of infants exposed to buprenorphine in the 30 days prior to delivery had neonatal abstinence syndrome, compared to 69.2% of those exposed to methadone (aRR, 0.73; 95% CI, 0.71-0.75).

The investigators also recorded data on preterm births.

Here, they found 14.4% of infants exposed to buprenorphine in early pregnancy and 24.9% of infants exposed to methadone (aRR, 0.58; 95%, 0.53-0.62) were preterm births.

For small size for gestational age, 12.1% of the buprenorphine group and 15.3% of the methadone group were in this category (aRR, 0.72; 95% CI, 0.66-0.80).

Low birth weight occurred in 8.3% and 14.9% of the cohorts, respectively (aRR, 0.56; 95% CI, 0.50-0.63).

Delivery by cesarean section occurred in 33.6% of the buprenorphine group in early pregnancy, compared to 33.1% of the methadone group (aRR, 1.02; 95% CI, 0.74-1.13).

The results of exposure in late pregnancy were consistent with results of exposure in early pregnancy.

“The use of buprenorphine in pregnancy was associated with a lower risk of adverse neonatal outcomes than methadone use; however, the risk of adverse maternal outcomes was similar among persons who received buprenorphine and those who received methadone,” the authors wrote.

The study, “Buprenorphine versus Methadone for Opioid Use Disorder in Pregnancy,” was published online in the New England Journal of Medicine.