Bennett, Bendersky and Lewis (2008) conducted a longitudinal study to investigate the effects of prenatal cocaine
exposure on children’s cognitive ability at the age of 4, 6 and 9 years old. Data on The Stanford-Binet IV intelligence test, children’s medical report and surveys from mother were analyzed. One advance of their study, as reported, is that they used a mixed model analysis to control for other substance abuse and other environmental factors. They found that
prenatal cocaine exposure caused lower IQ scores only in boys but not girls; and although their IQ score increase over time, they were consistently lower than the exposed girls and the non-exposed children. They also found that children of mothers/caregivers with higher verbal intelligence or from a more stimulating family environment have higher IQ scores.
Bennett et al.’s (2008 ) conclusion’s generalizability is limited because their sample is largely consisted of African American population.
Novak and Pelaez (2004) suggested that alcohol and cigarette smoking are two most widely studied substances affecting the development of fetus. Results from this study add to the existing evidence for the detrimental effects from substance exposure during pregnancy.