Similar, favorable results with prenatal buprenorphine/naloxone vs. buprenorphine alone

Key takeaways:

• Risks for adverse neonatal outcomes were lower with prenatal buprenorphine plus naloxone vs. buprenorphine alone.
• Maternal morbidity rates were similar with buprenorphine combination and buprenorphine alone.

Pregnant women with opioid use disorder treated with buprenorphine combined with naloxone had similar and, in some cases, more favorable neonatal and maternal outcomes vs. treatment with buprenorphine alone, researchers reported in JAMA.

“Outside of pregnancy, the effectiveness of buprenorphine/naloxone to prevent misuse has yielded mixed results, yet it has been consistently marketed as a way to reduce diversion,” Loreen Straub, MD, MS, investigator in the division of pharmacoepidemiology and pharmacoeconomics and instructor in the department of medicine at Brigham and Women’s Hospital and Harvard Medical School, and colleagues wrote. “However, in pregnancy, due to the uncertain risk of naloxone to the fetus, some guidelines recommend that individuals be switched to buprenorphine alone, despite its lacking properties to deter diversion.”

Straub and colleagues conducted a population-based cohort study using health care utilization data from 9,537 Medicaid-insured pregnant women with opioid use disorder from 2000 to 2018. All women were exposed to buprenorphine during the first trimester. Researchers compared those exposed to buprenorphine plus naloxone and buprenorphine alone during the first trimester.

Primary outcomes were major congenital malformations, low birth weight, neonatal abstinence syndrome, NICU admission, preterm birth, respiratory symptoms, small for gestational age, cesarean delivery and maternal morbidity.

Overall, 3,369 pregnant women (mean age, 28.8 years) were exposed to buprenorphine combined with naloxone during first trimester and 5,326 (mean age, 28.3 years) were exposed to buprenorphine alone or switched from the combination to buprenorphine alone by the end of the first trimester.

Pregnant women exposed to buprenorphine plus naloxone had lower risks for neonatal abstinence syndrome (weighted RR = 0.77; 95% CI, 0.7-0.84), NICU admission (weighted RR = 0.91; 95% CI, 0.85-0.98) and small for gestational age (weighted RR = 0.86; 95% CI, 0.75-0.98) compared with buprenorphine alone. Buprenorphine plus naloxone was associated with similar maternal morbidity rates as buprenorphine alone (weighted RR = 0.9; 95% CI, 0.68-1.19).

Researchers observed no differences in major congenital malformations overall, low birth weight, preterm birth, respiratory symptoms or cesarean delivery between the groups.

“For the outcomes assessed, compared with buprenorphine alone, buprenorphine combined with naloxone during pregnancy appears to be a safe treatment option,” the researchers wrote. “This supports the view that both formulations are reasonable options for treatment of opioid use disorder in pregnancy, affirming flexibility in collaborative treatment decision-making.”