DES (Diethylstilbestrol)

Originally Published: May 24, 2002 - Last Updated / Reviewed On: October 27, 2004
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Dear Alice,

Do you know anything about the Drug DES, taken by some women to enable them to have children? It seemed to have prevented miscarriages and the Dr. recommended this drug in the 1940s. Now women and men are having problems, for instance, cancer, etc. Do you have any more info on it?

Dear Reader,

You're exactly right. DES (it's fifty-cent name is diethylstilbestrol) was used between about 1940 and 1971 in pregnant women to prevent miscarriages. The drug is a laboratory-made form of the female hormone, estrogen. Nowadays, there are strict warnings against giving DES to pregnant women. It's still used for other conditions, such as problems with menstruation or menopause, problems with the functioning of the ovaries (primary ovarian failure), and as chemotherapy to treat some advanced cancers of the breast and prostate.

Originally, doctors thought giving DES to pregnant women could prevent miscarriage, stop pre-term labor, and treat other complications of pregnancy. Unfortunately, not only did the drug prove to be useless for these conditions, it also turned out to be harmful to the baby's developing reproductive organs. Both boy and girl babies are affected, although the problems don't show up until puberty or later.

Sons of mothers who were given DES may have the following problems:

  • abnormal urinary system
  • abnormal testicles
  • increased chance of developing cancer of the testicles
  • low sperm counts
  • possible infertility

Daughters of mothers who were given DES may have the following problems:

  • abnormalities of the tissue that lines the vagina
  • abnormalities of the cervix (the opening from the uterus into the vagina)
  • abnormally shaped uterus — may be unusually small or t-shaped (the normal uterus appears pear shaped on the outside, and its opening inside is an upside-down triangle)
  • abnormal fallopian tubes (the tubes that the egg travels down on its trip from the ovaries to the uterus)
  • increased risk of a pregnancy developing in a fallopian tube, instead of inside the uterus (this is called an ectopic pregnancy)
  • increased risk of developing an otherwise rare form of cancer of the vagina or cervix, clear cell adenocarcinoma, often affecting women between 15 and 27 years
  • difficulty becoming pregnant
  • increased risk of miscarriage or pre-term labor

If you think your mother was given DES during her pregnancy with you, you need to be carefully monitored every year, beginning at around fourteen years of age.

  • Men need to do regular testicular self-exams and have their testicles examined yearly by their health care provider.
  • Women need to see their health care provider yearly for a Pap smear and pelvic exam.
  • If you are a woman and you wish to become pregnant, find a specialist who is knowledgeable about taking care of pregnant DES daughters.
  • If you, yourself, were given DES, you may have an increased risk of developing breast cancer. You need to do monthly breast self-exams, see your health care provider yearly for annual breast exams, and follow your provider's recommendations for scheduling mammogram examinations.

A number of resources can provide more information on DES-related concerns, including:

Alice