Prenatal exposure to tobacco: I. Effects on physical growth at age three.

The height and weight of 714 children whose mothers smoked at the beginning of their pregnancies were assessed at three years of age. The children of women who quit smoking during pregnancy were taller and heavier than those of women who continued to smoke throughout pregnancy. Adjustment for maternal postpartum smoking status reduced the difference in weight, but had little effect on height. The differences in both height and weight at three years of age were greatly reduced when adjusted for size at birth and length of gestation. These results suggest that deficits associated with maternal smoking are not overcome by three years of age and that at least some of the observed anthropometric deficits may be extensions of deficits in fetal growth.