The Infant Development, Environment, and Lifestyle Study: Effects of Prenatal Methamphetamine Exposure, Polydrug Exposure, and Poverty on Intrauterine Growth

Objective: Methamphetamine use among pregnant women is an increasing problem in the United States. Effects of methamphetamine use during pregnancy on fetal growth have not been reported in large, prospective studies. We examined the neonatal growth effects of prenatal methamphetamine exposure in the multicenter, longitudinal Infant Development, Environment, and Lifestyle study.

Design/Method: The Infant Development, Environment, and Lifestyle study screened 13808 subjects at 4 clinical centers: 1618 were eligible and consented, among which 84 were methamphetamine exposed, and 1534 were unexposed. Those who were methamphetamine-exposed were identified by self-report and/or gas chromatography-mass spectrometry confirmation of amphetamine and metabolites in infant meconium. Those who were unexposed denied amphetamine use and had a negative meconium screen. Both groups included prenatal alcohol, tobacco, or marijuana use but excluded the use of opiates, LSD, PCP, or cocaine only. Neonatal parameters included birth weight and gestational age in weeks. One-way analysis of variance and linear regression analyses were conducted on birth weight by exposure. The relationship of methamphetamine exposure and the incidence of small for gestational age was analyzed using multivariate logistic regression analyses.

Results: The methamphetamine-exposed group was 3.5 times more likely to be small for gestational age than the unexposed group. Mothers who used tobacco during pregnancy were nearly 2 times more likely to have small-for-gestational-age infants. In addition, less maternal weight gain during pregnancy was more likely to result in a small-for-gestational-age infant. Birthweight in the methamphetamine-exposed group was lower than in the unexposed group.

Conclusions: These findings suggest that prenatal methamphetamine use is associated with fetal growth restriction after adjusting for covariates. Continued follow-up will determine if these infants are at increased risk for growth abnormalities in the future.