Methadone and perinatal outcomes: a retrospective cohort study.

Objective: The purpose of this study was to examine the relationship among methadone maintenance treatment, perinatal outcomes, and neonatal abstinence syndrome. Study design: This was a retrospective cohort study of 61,030 singleton births at a large maternity hospital from 2000-2007. Results: There were 618 (1%) women on methadone at delivery. Methadone-exposed women were more likely to be younger, to book late for antenatal care, and to be smokers. Methadone exposure was associated with an increased risk of very preterm birth <32 weeks of gestation (adjusted odds ratio [aOR], 2.47; 95% confidence interval [CI], 1.40-4.34), being small for gestational age