Tapering from Methadone or Buprenorphine during Pregnancy: Maternal and Neonatal Outcomes in Norway 1996-2009.

BACKGROUND The tapering of methadone or buprenorphine during pregnancy is an understudied and controversial issue. The aim of this study was to determine to what extent women tapered their opioid medication dose during pregnancy and what the neonatal outcomes were for those who tapered compared to the women who did not. METHODS The study was a mixed prospective/retrospective national cohort study of 123 Norwegian women in opioid maintenance treatment (OMT) during pregnancy and their neonates. A standardized questionnaire was administered to the women and medical information that could be used for verification was collected from hospitals and municipalities. RESULTS Two of the women came off the OMT-medication during pregnancy and another 15% tapered their OMT-medication dose more than 50%. The birth weights of methadone-exposed neonates of the women who tapered more than 50% were significantly higher than for the methadone-exposed neonates of the women tapering between 11 and 50%. No other significant differences were found. CONCLUSION Pregnant women in OMT who taper their OMT-medication dose should be monitored closely. We need studies that document the maternal well-being and fetal safety of maternal tapering of the OMT-medication during pregnancy.