Several other health outcomes have been studied that relate to the growth and health of children. This chapter discusses studies of the influence of ETS exposure on birthweight of the offspring of nonsmoking pregnant women and its influence on childhood growth and ear infections. For all postnatal outcomes, it is often not possible to differentiate effects of in utero exposure to tobacco smoke constituent from subsequent childhood exposures to ETS.
The fetus of a smoking mother is exposed in a unique way to the chemicals produced in cigarette smoke. Many studies have documented the adverse effect this relationship has on intrauterine fetal growth, especially during the third trimester of pregnancy (U.S. Department of Health and Human Services, 1976). Maternal cigarette smoking apparently affects fetal oxygenation, due to high levels of carboxyhemoglobin in the blood of both mother and child (Abel, 1980). However, the effects on the fetus of a nonsmoking mother chronically exposed to ETS are not well documented. Some studies have indirectly approached this problem by evaluating paternal cigarette smoking and birth outcomes in nonsmoking pregnant women.
Some early studies of paternal smoking and birthweight demonstrated a dose-response relationship that was discounted as