Opioid maintenance treatment during pregnancy: occurrence and severity of neonatal abstinence syndrome. A national prospective study.

BACKGROUND: Opioid maintenance treatment (OMT) is widely used to treat pregnant women with a history of opioid dependence. This study investigated whether maternal methadone/buprenorphine dose and nicotine use in pregnancy affects the occurrence and duration of neonatal abstinence syndrome (NAS) in the infant.

METHODS: Forty-one pregnant women from OMT programmes in Norway who gave birth between January 2005 and January 2007 were enrolled in a national prospective study. Thirty-eight women (81% of the population) were interviewed in the last trimester of pregnancy and 3 months after delivery. Data from the European Addiction Severity Index and a questionnaire measuring enrolled birth information were compared with medical records and urine analyses.

RESULTS: Treatment requiring NAS occurred in 58% of the methadone-exposed and in 67% of the buprenorphine-exposed infants. There was no significant relationship between a maternal dose of methadone or buprenorphine in pregnancy and NAS treatment duration for the infant. The mean number of cigarettes consumed correlated significantly with NAS treatment duration for the methadone group. Birth weight for the methadone group was approximately 200 g above international findings despite high doses during pregnancy.

CONCLUSIONS: Maternal methadone/buprenorphine dose predicted neither the occurrence nor the need for NAS treatment for the infant.