and Hirsch, 1981). In 1951 the FDA concluded that DES was safe for use during pregnancy and stopped requiring manufacturers to complete NDAs prior to marketing the drug as a preventive against miscarriage (Mascaro, 1991).


In 1971 an article in the New England Journal of Medicine reported that between 1966 and 1971 seven cases of clear-cell adenocarcinoma (CCA) had been found in teenage girls (Herbst et al., 1971). CCA is an extremely rare cancer, particularly in young women. The common element to these seven cases was that their mothers had taken DES during their pregnancies. In that same year, the FDA banned the use of DES as a miscarriage preventive; but by that time, an estimated 1.5 million babies had been exposed to DES. Thirty thousand were exposed in 1971 alone (Weitzner and Hirsch, 1981).

Research has found that DES interferes with the formation of normal genital tissue during fetal development. Many studies have found possible associations between DES exposure and abnormalities in daughters of women who took DES while pregnant. These studies, including one looking at DES daughters whose mothers were involved in the University of Chicago experiments, have found possible associations between DES exposure and vaginal and cervical dysplasia (a type of abnormal tissue that either reverts with time or progresses slowly to cancer); adenosis (glandular proliferation); cervical ridges and cervical erosion; uterine structural abnormalities, such as a T-shape of the endometrial cavity and/or an unusually small uterus; uterine hypoplasia (underdeveloped cells); infertility; menstrual irregularities; ectopic pregnancies; fetal death and premature birth; and breast and reproductive-tract cancers (Weitzner and Hirsch, 1981). The pathologic changes were more common in women exposed to high DES doses and those exposed early in gestation. It is estimated that there are almost two million ''DES daughters" now of childbearing age (NIH, 1992).

Injury to male babies, or DES sons, has also been reported. No malignant tumors have been reported, but certain genital and semen abnormalities are more common in men exposed to DES in utero than in men not exposed to DES. These abnormalities include penile bleeding, testicular masses, epididymal cysts, hypoplastic testes, and cryptorchidism (undescended testicle) (NIH, 1992). One article reported that one in three DES sons is sterile (Weitzner and Hirsch, 1981). Other authors call for more studies to determine whether the observed abnormalities are correlated with an increased risk of infertility (NIH, 1992).

There have also been allegations of injury to third generations. Two legal actions were initiated on behalf of DES granddaughters who claim

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