Intrauterine substance exposures and Wechsler Individual Achievement Test-II scores at 11 years of age

Abstract

The goal of this study was to evaluate whether intrauterine exposure to cocaine, alcohol, tobacco, or marijuana was associated with unique variance in children's academic achievement test scores after controlling for other substance exposures and contextual variables. Academic achievement scores (Wechsler Individual Achievement Test-Second Edition (WIAT-II)) were collected from 119, low-income, urban 11-year-olds enrolled in a prospective longitudinal study of intrauterine cocaine exposure (IUCE). Newborn recruitment eligibility included >36 weeks gestational age, no neonatal intensive care, no intrauterine exposure to illicit drugs except cocaine or marijuana, and no evidence of fetal alcohol syndrome (FAS). Intrauterine substance exposures (cocaine, marijuana, alcohol, tobacco) were documented in the newborn period using biological assays and maternal self-report. Multivariate analyses evaluated the relationship of each intrauterine exposure and each WIAT-II score controlling for contextual variables and the other substance exposures. In secondary analyses, the Child Depression Inventory (CDI) was added to final models. Results indicate that neither IUCE nor intrauterine exposure to marijuana or tobacco was associated with lower WIAT-II scores in multivariable analyses. Intrauterine alcohol exposure predicted significant variance in Math Reasoning and Spelling scores, but inclusion of children's depressive symptoms attenuated the relationship. Lower maternal education and maternal US birth were also associated with lower WIAT-II scores. Our analyses indicate that among low-income, urban 11-year-olds without a diagnosis of FAS, intrauterine alcohol exposure was negatively associated with math and spelling achievement scores after controlling for other intrauterine substance exposures and contextual factors. That relationship in this sample was partially mediated by children's depressive symptoms, but we cannot establish whether these lower achievement scores precede or follow depressive symptoms. Our findings highlight that neurobehavioral studies evaluating a primary potential neuroteratogen should evaluate other associated intrauterine exposures and contextual factors.