Methadone maintenance in pregnancy: a reappraisal

The purpose of this study is to evaluate women receiving methadone maintenance during pregnancy.

Thirty-two pregnancies in women receiving methadone maintenance were matched by gestational age to women with a positive urine screen for cocaine at delivery and to drug-free controls. Pregnancy outcome variables were compared, including birth weight and neonatal morbidity. Analysis was by chi2 and t test with significance set at .05.

Birth weight of methadone-exposed infants was 2748 g versus 2925 g for cocaine and 3032 g for controls, P = not significant. Birth weight comparison with a 50-mg maternal methadone cutoff dose was not different. A head circumference for methadone infants of 32.4 +/- 4.7 cm was significantly less than controls, 33.5 +/- 4.0 cm, P < .04, but not different from infants of cocaine users, 32.8 +/- 3.1 cm. Women using cocaine had a significantly higher incidence of meconium in labor compared with methadone and controls. Of women taking methadone 27 of 32 (84.3%) were positive for other drugs of abuse in the last screen before or at delivery. Cocaine 12 of 32 (37.5%), other opiates 13 of 32 (40.6%), and marijuana 14 of 32 (43.7%) were the most prevalent. Neonatal withdrawal occurred in 23 of 32 (72%) women taking methadone. The neonates of women using < 50 mg of methadone were as likely to withdraw as those women using > or = 50 mg, 61.5% versus 79.0%, P not significant. Three neonates in the methadone group (9.3%) had major congenital anomalies, with 2 of the 3 (66.6%) resulting in mortality.

Birth outcome is not significantly different between methadone and cocaine users. Women receiving methadone maintenance are likely to abuse other illicit drugs.