A new systematic review has found that buprenorphine-naloxone may be associated with a lower risk of neonatal abstinence syndrome (NAS) compared with buprenorphine alone in pregnant individuals with opioid use disorder. The findings, published in the journal Drug and Alcohol Dependence, suggest a potential alternative treatment option that could improve neonatal outcomes, though further research is needed to confirm these results.
The study analysed data from six retrospective cohorts comprising 9,348 mother-infant pairs, of whom 38.3% received buprenorphine-naloxone. The primary outcome was the incidence of NAS, a withdrawal condition affecting newborns exposed to opioids in the womb. The results indicated that neonates born to mothers treated with buprenorphine-naloxone had a lower likelihood of developing NAS compared with those whose mothers received buprenorphine alone. Additionally, the risk of small-for-gestational-age infants was reduced in the buprenorphine-naloxone group.
The standard of care for opioid use disorder during pregnancy has traditionally included either methadone or buprenorphine. However, buprenorphine-naloxone has been considered as a possible alternative due to its lower potential for misuse. Unlike buprenorphine alone, the addition of naloxone is intended to deter non-prescribed use by preventing opioid effects when the medication is taken improperly. While it has been widely used in non-pregnant individuals, its safety and effectiveness during pregnancy have been less clear, leading to some hesitation among healthcare providers in adopting it as a primary treatment.
Despite the promising findings on NAS reduction, the study found no significant differences between buprenorphine-naloxone and buprenorphine alone in other key pregnancy and neonatal outcomes. These included rates of preterm birth, low birth weight, caesarean delivery, and neonatal intensive care unit admissions. This suggests that while buprenorphine-naloxone may reduce the likelihood of NAS, it does not necessarily confer additional benefits for broader pregnancy-related complications.
The study’s authors highlight the need for further research, particularly through randomised controlled trials, to validate the findings. The existing data is drawn from non-randomised cohort studies, which carry potential biases and confounding factors that could influence the results. Variability in study designs, dosage regimens, and patient characteristics further complicates direct comparisons between treatment groups.
One key concern with buprenorphine-naloxone in pregnancy is the potential risk of withdrawal symptoms if the medication is not taken as prescribed. Naloxone has limited absorption when taken sublingually, but if administered improperly, it can precipitate withdrawal, which may pose risks for both the mother and the fetus. For this reason, healthcare providers have historically favoured buprenorphine alone during pregnancy. However, with growing evidence suggesting a potential benefit in reducing NAS, some clinicians may reconsider its use in specific cases where the risk of misuse is a significant concern.
While the study provides important insights, medical professionals stress that treatment decisions should remain highly individualised. Factors such as patient history, risk of relapse, and access to comprehensive prenatal care all play a role in determining the most appropriate approach. Ongoing research will be essential in establishing clear guidelines for the use of buprenorphine-naloxone in pregnancy.
