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DES Babies Face Increased Infertility, Breast Cancer Risk and More

Throughout the years, we have heard many concerns about the effects of diethylstilbestrol, known as DES, a synthetic form of estrogen used from the 1940s to the early 1970s to prevent certain complications of pregnancy, such as miscarriage. In 1971, the U.S. Food and Drug Administration notified physicians that DES should not be prescribed to pregnant women after discovery of a rare form of vaginal cancer in the daughters of women who took DES; however, that left between 5 million and 10 million pregnant women and babies who had been exposed to the drug.

Now, a National Cancer Institute (NCI) study has followed the daughters of mothers given DES while pregnant. They found that exposure to the drug while in utero is associated with many reproductive problems and an increased risk of certain cancers and pre-cancerous conditions. The study, published in the New England Journal of Medicine involved more than 6,500 women (4,600 exposed and 1,900 unexposed and showed that the women exposed had an increased risk of 12 medical conditions.

“Our study carefully documents elevated risk for DES-exposed daughters for a host of medical problems—many of them also quite common in the general population,” said study author Robert N. Hoover, M.D., director of the Epidemiology and Biostatistics Program in NCI’s Division of Cancer Epidemiology and Genetics.

Infertility and Reproductive Issues

Women exposed to DES in utero were at a twofold higher risk of infertility and a fivefold risk of having a preterm delivery. Of all DES-exposed women, 1 in 5 will experience some level of infertility because of their exposure. And of all those exposed women who are successful in having at least one birth, 1 in 3 will have a preterm delivery due to DES.

The researchers found risks for DES daughters compared to non-exposed women for:

  • neonatal death (eight times higher)
  • pre-term delivery (4.7 times higher)
  • loss of second trimester pregnancy (3.8 times higher)
  • ectopic pregnancy (3.7 times higher)
  • stillbirth (2.4 times higher)
  • infertility (2.4 times higher)
  • early menopause (2.4 times higher)
  • first trimester miscarriage (1.6 times higher)
  • preeclampsia (1.4 times higher)


DES-exposed daughters have about 40 times the risk of developing clear-cell adenocarcinoma (CCA), a cancer of the vagina, than unexposed women; however, CCA is still a rare disease, occurring in 1 in 1,000 DES-exposed daughters. But DES-exposed women are more than twice as likely to develop pre-cancerous cells in the cervix or vagina and have an 80 percent higher chance of developing breast cancer after age 40.

The researchers found risks for DES daughters compared to non-exposed women for:

  • clear-cell adenocarcinoma (CCA) (40 times higher)
  • cervical intraepithelial neoplasia (2.3 times higher)
  • breast cancer (1.8 times higher)

The women in this study were followed as part of the NCI’s DES Follow-up Study, which began in 1992. NCI researchers will continue to study DES-exposed daughters as they move into menopausal years.

For more information about DES exposure and cancer risk, click here for a NIH fact sheet.


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