Methadone and perinatal outcomes: a retrospective cohort study

The purpose of this study was to examine the relationship among methadone maintenance treatment, perinatal outcomes, and neonatal abstinence syndrome.

This was a retrospective cohort study of 61,030 singleton births at a large maternity hospital from 2000-2007.

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 <10th percentile (aOR, 3.27; 95% CI, 2.49-4.28), admission to the neonatal unit (aOR, 9.14; 95% CI, 7.21-11.57), and diagnosis of a major congenital anomaly (aOR, 1.94; 95% CI, 1.10-3.43). There was a dose-response relationship between methadone and neonatal abstinence syndrome.

Methadone exposure is associated with an increased risk of adverse perinatal outcomes, even when known adverse sociodemographic factors have been accounted for. Methadone dose at delivery is 1 of the determinants of neonatal abstinence syndrome.