Teratogen update: carcinogenesis and teratogenesis associated with exposure to diethylstilbestrol (DES) in utero.

Exposure of the human fetus to physician-prescribed diethylstilbestrol and other synthetic estrogens (collectively referred to as "DES") led to an important iatrogenic epidemic. In the United States alone, at least four million fetuses and their mothers had a substantial exposure to these estrogens now known to be mild carcinogens and potent teratogens. Mothers exposed to DES may have a somewhat higher risk of breast cancer than women who were not exposed. The sequelae of in utero exposure of daughters include clear cell adenocarcinoma of the vagina and cervix, various gross anomalies of the genital tract that are associated with adverse outcomes of pregnancy, vaginal adenosis and other vaginal epithelial changes, and other possible health effects that have not yet been fully evaluated. Among sons exposed in utero to DES, no increase in the incidence of any cancer has been reported, but several anomalies of the genital tract have been described, and it is possible that some social behaviors are modified. Although the grandchildren of the DES-exposed daughters and sons have not been shown to have any abnormalities, some of them have been the products of short gestations. Future research, being funded by the National Cancer Institute, will permit monitoring of the DES-exposed population to determine whether any other abnormalities will become apparent in them.