Alcohol, tobacco and marijuana use among pregnant teenagers: 6-year follow-up of offspring growth effects.

This prospective study evaluated the relations between maternal alcohol, tobacco and marijuana use during pregnancy and children's growth at 6 years. In this cohort of pregnant teenagers and their offspring, mothers were recruited from an urban prenatal clinic between 1990 and 1995, and observed from their fourth prenatal month. At the delivery assessment, there were 413 live-born singletons. At the 6-year visit, 345 children and mothers were evaluated. Prenatal alcohol and marijuana exposure were significantly associated with growth deficits, after controlling statistically for other prenatal substance use, current maternal substance use, current environmental tobacco exposure (ETS) and sociodemographic and growth-related covariates. There was a significant negative association between the second and third trimester alcohol exposure and offspring height. Third trimester alcohol exposure predicted reduced skinfold thickness. Exposure to any prenatal marijuana in the second trimester was significantly associated with shorter stature. First trimester tobacco exposure was associated with increased skinfold thickness among the 6-year-olds. The effects of prenatal alcohol exposure on growth at birth persisted in older children despite a low level of exposure during gestation. Effects of prenatal marijuana exposure on reduced height were not anticipated and occurred only when use was categorized as any/none. These data are consistent with an emerging body of evidence indicating that, by contrast to the growth deficits associated with smoking during pregnancy, which are evident at birth, the shorter stature associated with prenatal alcohol exposure continues to be evident during childhood.