Gestational cocaine exposure and intrauterine growth: maternal lifestyle study.

Objective: To estimate the effects of cocaine exposure on intrauterine growth and to investigate at what point in gestation growth deviation would be manifested.

Methods: This is a secondary analysis of data from a multicenter project, the Maternal Lifestyle Study, designed to determine infant outcomes of in utero cocaine or opiates exposure. Four centers of the National Institute of Child Health and Human Development Neonatal Research Network enrolled 11,811 maternal-infant dyads. A total of 1072 infants were cocaine exposed, 7565 were cocaine negative by maternal history and meconium results, and 3174 were excluded from analysis because of unconfirmed negative exposure. Outcome measures included birth weight, length, and head circumference.

Results: Percentile estimates for birth weight, length, and head circumference revealed growth deceleration in cocaine-exposed infants evident after 32 weeks' gestation. There was significant interaction between cocaine and gestational age. After controlling for confounders, at 40 weeks' gestation, cocaine exposure was estimated to be associated with a decrease of 151 g, 0.71 cm, and 0.43 cm in birth weight, length, and head circumference, respectively. Smoking had a negative impact on all growth measurements, with some indication of a dose-effect relationship. Heavy alcohol use was associated with decrease in weight and length only. Opiates had significant effect only on birth weight.

Conclusion: In utero cocaine exposure is associated with growth deceleration involving all measurements, becoming more pronounced with advancing gestation.