Buprenorphine-naloxone combo appears safe for treating opioid use disorder in pregnancy
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Women receiving buprenorphine-naloxone therapy for the treatment of opioid use disorder during pregnancy had similar outcomes vs. buprenorphine therapy alone in terms of maternal and neonatal health, data show.
“Our results provide an encouraging reference that buprenorphine and naloxone combination therapy could be an oral opioid maintenance treatment during pregnancy,” Minna M. Kanervo, a doctoral researcher at the University of Helsinki, told Healio. “As in previous studies, our findings also suggest that a stable dose of substitution therapy is preferable to dose reduction during pregnancy, since the drug abuse risk increases with dose reduction, and secondly, the dose seems to be unrelated to the newborn’s need of medication for withdrawal symptoms.”
Characterizing the cohort
Kanervo and colleagues followed 69 pregnant women who received the same opioid maintenance treatment from conception to delivery at Helsinki University Women’s Hospital from 2011 to 2018. There was one twin delivery and one stillbirth, so final analyses included 37 mother-infant dyads in the buprenorphine-naloxone group, 15 dyads in the buprenorphine-only group and 15 dyads in the methadone group.
Most women reported smoking before (97%) and during (93%) pregnancy, and about 20% of women reported using alcohol during pregnancy. Approximately half of the study population self-reported or tested positive for illicit drug use during pregnancy, but it was more common in the methadone group vs. the buprenorphine groups (P = .001).
“As a pediatrician, I am concerned about this because of fetal drug exposure, but also in view of the circumstances of the child’s life if the mother or both parents continue to use substances after the child is born,” Kanervo said.
Compared with women in either buprenorphine group, women in the methadone group more commonly had a psychiatric comorbidity (P = .025) and an active hepatitis C virus infection (P = .013).
Pregnancy outcomes
Compared with the general population of pregnant Finnish women, those receiving opioid maintenance treatment were the same age but were less likely to be giving birth for the first time (41% vs. 16%).
In total, there were 53 (79%) spontaneous vaginal deliveries and 13 (19%) cesarean sections in the study cohort. Pregnancy complications occurred at similar rates compared with the general population of pregnant Finnish women, and deliveries were “mainly uneventful,” according to the researchers.
All but three infants (96%) were born full term, and all had 5-minute Apgar scores of at least five. One infant (3%) in the buprenorphine-naloxone group and two (13%) in the methadone group had scores of five or six.
Infants in the study cohort were smaller than those in the general population, with 15 (22%) born small for gestational age. Infants in the methadone group were the smallest among the cohort, although differences were not statistically significant between therapies.
Congenital malformations were minor and not common, with no significant differences between groups.
There was the lowest need for neonatal opioid withdrawal syndrome treatment in the buprenorphine-naloxone group (51%) and the highest need in the methadone group (87%). Compared with infants in either buprenorphine group, those in the methadone group were more likely to need treatment for neonatal opioid withdrawal syndrome (56% vs. 87%; P = .029).
Analyses of neonates prenatally exposed to illicit drugs showed that those in the methadone group were more likely to need treatment for neonatal opioid withdrawal syndrome (P = .048).
“Because buprenorphine-naloxone has a lower abuse potential than buprenorphine or methadone, it could be a treatment option during pregnancy, but larger studies are needed to confirm our results,” Kanervo told Healio.