Perinatal and developmental outcome of infants exposed to methadone in-utero.

The purpose of this research is to delineate the effects of methadone exposure in-utero. Subjects were 141 infants born to drug dependent women maintained on methadone during pregnancy and 127 non-drug exposed comparison infants matched for race, maternal age, and socioeconomic status. Methadone exposed infants had smaller birth weights than comparison infants. Differences were also found in head circumference. However, this difference was not clinically significant but rather reflects the relationship between birth weight and head circumference. No difference was found between groups in mental development. One hundred and five methadone exposed infants and 63 comparison infants were evaluated with the Bayley Scale of Mental Development at 6 months of age. Mean Bayley Mental Development scores for methadone exposed infants and comparison infants were 103 and 105 respectively. These data suggest that while methadone exposure in-utero is associated with lower birth weight and head circumference, by six months of age, these infants do not exhibit any general developmental sequelae.