The smoking addiction of pregnant women and the consequences on their offspring's intellectual development.

Many scientists have studied the effects of smoking by pregnant women on intrauterine development. Because nicotine and other toxic substances in cigarette smoke are not stopped by the placental barrier, there is a risk that the development of the child could be hindered. It has been shown, for instance, that babies whose mothers smoked during pregnancy have lower size and weight at birth. Few authors have studied the consequences a mother's pre-natal smoking may have on the intellectual development of her child. We compared two samples of children, aged 4 to 5, and aged 6 to 7 (40 children in total), whose mothers had smoked during pregnancy, with two samples of 40 children of the same ages whose mothers had not smoked. We tested them on the Wechsler scale. The social and cultural levels were equivalent. We found a difference of more than 15 IQ points in favor of the children of nonsmoking mothers. These results permit us to suppose that smoking during pregnancy hinders the intellectual development of the child.