Additional pregnancy, child, and caregiver data were also collected to control for potential confounding variables in analyses. Information about the use of alcohol, cigarettes and other drugs during pregnancy was collected antenatally by maternal interview at each prenatal visit. Self report of alcohol use during the 2 weeks preceding the pregnancy visit was converted to AAD and averaged across pregnancy. The number of cigarettes smoked per day during each 2-week period was also recorded and averaged across pregnancy. Data for other drug use (including marijuana and opiates) was also collected antenatally. Maternal drug use during pregnancy was also assessed retrospectively at the 7-year follow-up. Neonatal and maternal information was obtained from medical records at birth. At the 7-year follow-up, caregivers were queried about drug, alcohol and cigarette use in the home, completed demographic forms, and a quality of home environment assessment (based on the HOME; Caldwell & Bradley, 1984) was performed in the laboratory. Whole blood lead levels were assayed by the institutional laboratory and recorded in μg/dl.
