To assess the safety of buprenorphine compared with methadone to treat pregnant women with opioid use disorder.
We searched PubMed, Embase and the Cochrane Library from inception through February 2015 for randomized controlled trials (RCT) and observational cohort studies (OBS) that compared buprenorphine with methadone for treating opioid-dependent pregnant women. Two reviewers independently assessed titles and abstracts of all search results and full texts of potentially eligible studies reporting original data for maternal/fetal/infant death, preterm birth, fetal growth outcomes, fetal/congenital anomalies, fetal/child neurodevelopment, and/or maternal adverse events. We ascertained each study’s risk of bias using validated instruments and assessed the strength of evidence for each outcome using established methods. We computed effect sizes using random-effects models for each outcome with 2 or more studies.
Three RCTs (N = 223) and 15 cohort OBS (N = 1923) met inclusion criteria. In meta-analyses using unadjusted data and methadone as comparator, buprenorphine was associated with lower risk of preterm birth [RCT risk ratio (RR) 0.40 (95% CI 0.18, 0.91); OBS RR 0.67 (95% CI 0.50, 0.90)], greater birth weight [RCT weighted mean difference (WMD) 277 g (95% CI 104, 450); OBS WMD 265 g (95% CI 196, 335)] and larger head circumference [RCT WMD 0.90 cm (95% CI 0.14, 1.66); OBS WMD 0.68 cm (95% CI 0.41, 0.94)]. No treatment differences were observed for spontaneous fetal death, fetal/congenital anomalies and other fetal growth measures, although the power to detect such differences may be inadequate due to small sample sizes.
Moderately strong evidence indicates lower risk of preterm birth, greater birth weight and larger head circumference with buprenorphine treatment of maternal opioid use disorder during pregnancy compared with methadone treatment, and no greater harms.
Source: Addiction Journal – Accepted manuscript online May 25, 2016