A prospective study of prenatal cocaine exposure: language, play, and global cognitive abilities in 2-year olds

Abstract

The relationship between prenatal cocaine exposure and 2-year developmental outcome was examined in a sample of 200, 2-year-old children followed prospectively from birth. Adverse cocaine effects were hypothesized to emerge in highly-exposed children, rather than the whole group, and in the specific developmental abilities of language and play, rather than global cognitive skills. Cocaine-exposed toddlers (n = 100) were successfully group-matched with non-cocaine-exposed toddlers (n = 100) on selected maternal demographics, child characteristics, and other prenatal drug exposures. Woman in both groups completed 12 years of education, were in their mid-20's, primarily white, and similar on marijuana use and binge alcohol use during pregnancy (but greater parity and cigarette use for cocaine-using women). Prenatal cocaine use was gathered via self report on the day after delivery and later verified by maternal hair analysis. Productive child language was obtained from caregiver report and videotaped, caregiver-child interaction. Quality of play behaviors were coded from videotaped, child-alone play. Global cognitive skills were assessed with the Bayley. Total grams of cocaine used throughout pregnancy was the predictor in dose-response regression analyses, while group differences were compared with t-tests. Confounds not dealt with by study design (e.g., postnatal environment) were adjusted in statistical analyses.Neither dose-response nor group difference analyses revealed independent, adverse effects of prenatal cocaine exposure. For both groups, productive language was within normal age limits, global cognitive skills were in the low-average range, and the quality of most play behaviors was age- and context-appropriate. However, subtle signs of immature play behaviors (e.g., unelaborated play) were exhibited by both groups and a subset of children in both groups exhibited general cognitive delay. Findings suggest that early language, play, and general cognitive abilities are not adversely affected by cocaine, even for the most highly-cocaine-exposed children, but may be more related to moderating postnatal environmental factors. Results confirm the need to examine developmental outcome in terms of the complex interrelationships between cocaine exposure and the risk and protective factors in the postnatal environment.