Diethylstilbestrol (DES), a synthetic estrogen, was prescribed to millions of pregnant women in the United States from 1938 to 1971. Manufactured under many different names (see DES Names), the drug was marketed to prevent miscarriage or premature birth by supplementing a pregnant woman's natural estrogen production.  It was postulated that administering estrogen would induce placental hormone production; therefore, sustaining a viable pregnancy.  Despite a landmark study in the early 1950s finding DES ineffective in preventing miscarriage and premature birth (Dieckmann, et al. 1953) and subsequent research showing harm to the developing fetus, it was not until 1971 that the Food and Drug Administration issued a warning about the damaging effects of DES.  In the United States, it is estimated that between 5 and 10 million people were exposed to DES during the years it was prescribed.  DES was similarly prescribed in several European countries from the 1950s into the 1970s and may still be used in developing countries.

 

    Although DES is no longer prescribed to pregnant women in the United States, DES exposure continues to affect many lives:

 

    DES is associated with a number of adverse health effects; some of those health effects, including third-generation effects, are still unknown. Research to date suggests that health risks for daughters born to DES

mothers include:

 

   •    Increased risk of clear cell adenocarcinoma (CCA), a rare form of vaginal cancer

   •    Structural differences in reproductive anatomy

   •    Increased risk of intraepithelial dysplasia and neoplasia

   •    Increased risk of infertility

   •    Increased risk of pregnancy complications

 

    DES mothers, or women prescribed DES, appear to also have increased risk of breast cancer. DES sons‹boys exposed to DES in utero‹have an increased risk of being born with genital abnormalities.