The effects of in utero exposure to polychlorinated biphenyls (PCBs) on cognitive function in 212 children at 11 years of age were tested at Wayne State University, Detroit, MI. Prenatal exposure to PCBs from maternal ingestion of contaminated Lake Michigan fish was associated with significantly lower full-scale and verbal IQ scores. Concentrations of PCBs in maternal serum and milk at delivery, only slightly higher than in the general population, caused long-term intellectual impairment, especially affecting memory, attention, and reading comprehension. 
COMMENT. Deficits in short-term memory and developmental delays, previously noted in infants and at 4 years of age in children exposed to PCBs in utero, have now been demonstrated in children tested at 11 years of age. PCBs may have a long-term adverse effect on cognitive function, and prenatal exposure to these environmental toxins should be included among potential causes of attention deficit disorders in children.