Diethylstilbestrol (DES)


DES is an estrogen that was first manufactured in 1938 and is called a synthetic estrogen as it was created in a laboratory and is not a natural human estrogen. During 1938 -1971 physicians prescribed DES to prevent miscarriages and other pregnancy problems as it was thought that these issues occurred due to women not producing enough estrogen naturally. Women who took DES do not have the same concerns as the children that were in the womb when they took DES. The “DES Mothers” have been found to have a slightly higher risk of breast cancer but do not have the same, whereas, the “DES Daughters” have been found to have a very slightly increased risk of vaginal cancer, reproductive tract structural chances and pregnancy complications, and “DES Sons” are at an increased risk of non-cancerous epididymal cysts.


In 1953 research showed that DES did not prevent miscarriages or premature births. However physicians continued to prescribe the medication until 1971. As a result, between 5-10 million pregnant women and the children they were pregnant with at the time were exposed to DES. In 1971 the Food and Drug Administration (FDA) advised physicians to stop prescribing DES as a published study identified that DES was a cause of Clear Cell Adenocarcinoma (CCA) –a rare vaginal cancer found in both girls and young women who were exposed in the womb.


1/3 of DES daughters are at an increased risk for reproductive tract structural differences such as: T shaped uterus, cervical or fallopian tube abnormalities; as well as pregnancy complication including ectopic (tubal) pregnancy and preterm or early delivery, as well as possible infertility. Most DES Daughters will be able to conceive and carry a baby to term. All of these health effects can also occur in women NOT exposed to DES –it is the percentage that varies. For example:

  • Approximately 20% of DES Daughters experience pre-term labor, compared to 8% of unexposed women.
  • DES Daughters are 40 times more likely to develop CCA of the vagina or cervix than women not exposed to DES -1 in 1,000 DES Daughters may be expected to develop this.
  • 64% of DES Daughters will deliver a full-term baby in their first pregnancy, compared to 85% of UNexposed women.
  • 20% of DES Daughters had a miscarriage during their first pregnancy, whereas only about 10% of unexposed women.
  • Reports show that about 24% of DES Daughters were unable to become pregnant, compared with 18% of unexposed women.  (DES exposure was most strongly associated with infertility caused by structural changes of the uterus.
  • The risk of ectopic pregnancy is 3-5 times higher for DES Daughters.


Unfortunately no medical test can detect DES exposure. However, if you have been exposed to DES or are unsure your doctor can do a pelvic exam to check for any structural changes and a pap smear to check for any cervical or vaginal abnormalities. In addition the doctor can do a colposcopy (viewing the vagina and cervix with a microscope) and apply vinegar or iodine in order to identify any abnormal areas. DES Daughters are considered high risk and should have an annual pap smear and pelvic exam –more often if any abnormalities are found.

If you have experienced infertility a hysterosalpingogram – a type of x-ray –can show if there are any structural abnormalities in the upper genital tract.

Many of the risk factors associated with DES exposure during pregnancy are treatable if you take action.  DES Daughters are considered high risk for pregnancy; so make sure to inform your OB doctor. Some tests that are recommended for OB care by the National Cancer Institute are:

  • A blood test (B-HCG) every 48 hours until an intrauterine pregnancy is confirmed
  • An ultrasound may be helpful to rule out an ectopic pregnancy
  • Regular inspection and palpation of the cervix starting at 12 weeks to check for dilation or effacement (shortening or thinning of the tissue)
  • In the third trimester it is important to be aware of the signs and symptoms of preterm labor and have weekly examinations


These recommendations may vary for each individual patient so please check with your provider.


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