Outcomes of neonates conceived on methadone maintenance therapy.

To assess potential risks related to the duration or total amount of fetal methadone exposure during gestation, we compared babies of women who conceived and maintained on methadone throughout pregnancy with babies of women who began methadone treatment during the second or third trimester. Babies conceived on methadone were exposed to the medication for a mean of 37.4 weeks at a mean dose of 110 mg/day, whereas comparison babies were exposed for a mean of 13.1 weeks at a mean dose of 93 mg/day. There were no significant between-group differences in the frequency of treatment of neonatal abstinence, days hospitalized, birth weight, or gestational age. Babies conceived on methadone were significantly less likely to test positive for illicit drugs at delivery as compared with babies conceived off methadone (positive toxicology, 9.1% vs. 34.3%, respectively). Methadone exposure during the entire gestational period was associated with better drug-treatment outcomes but was not associated with more severe neonatal abstinence.