By OBOS Common Medical Conditions Contributors |

The DES story is a cautionary tale of medical care gone awry.

DES (diethylstilbestrol) is a powerful synthetic estrogen that crosses the placenta of pregnant women and can damage the reproductive system of the developing fetus. DES may also affect other body systems: endocrine, immune, skeletal, and neurological. This drug was prescribed to an estimated 4.8 million U.S. women between 1938 and 1971 (and sometimes beyond) in the mistaken belief that it would prevent miscarriage.

In fact, DES was untested for pregnancy use or safety, and studies showing that it did not prevent miscarriage were ignored for almost two decades. It was aggressively marketed and used worldwide, under more than two hundred brand names, in pills, injections, and suppositories, and sometimes in pregnancy vitamins, until it was found to be linked to a rare form of vaginal/cervical cancer (clear cell adenocarcinoma of the vagina or cervix) in women who were exposed when their mother took the drug during pregnancy.

DES exposure during an embryo’s development has lifelong effects that can’t be reversed. For example, the cells of the endometrium (uterine lining) of an adult woman who was exposed to DES in the womb will act differently from those of a woman who wasn’t exposed.

Outside the United States, DES was also prescribed during pregnancy in Canada, Ireland, France, the United Kingdom, the Netherlands, Australia, New Zealand, Israel, Russia, and Poland. Other countries may include Belgium, Czechoslovakia, Finland, Germany, Italy, Norway, Portugal, Spain, and Switzerland. DES use in some of these countries extended beyond the 1970s.

Large generational studies of DES mothers, daughters, sons, and granddaughters by the National Cancer Institute DES Follow-up Study continue in the United States as a result of efforts by DES advocacy groups.

Who Is Exposed and How to Find Out

Several million people have been exposed to DES, most without knowing it. If you were born between 1938 and 1971, if your mother had problems with any of her pregnancies or remembers taking anything when she was pregnant with you, you could have been exposed. (DES was most widely used between 1947 and 1965, when “wonder drugs” were popular.)

However, with the passage of time it has become increasingly difficult to be sure by finding medical records. Some health care providers or facilities no longer have old records or refuse to give out the information. Any women in the appropriate age group should try to find out if she is at risk. See DES Action for the latest information about DES exposure.

Medical Problems and Care for DES Daughters

One out of every thousand DES daughters is likely to develop clear-cell adenocarcinoma, a rare type of vaginal or cervical cancer. It has occurred in girls as young as seven and women up to age 40, with the peak at ages 15 to 22. Although the number of cases of clear-cell cancer has declined in the last three decades (mirroring decreased use of DES beginning in the 1970s), it continues to be found in DES daughters, some in their fifties. There is a suggestion of a possible increase in the number of cases as DES daughters reach menopause. If you are a DES daughter, you need a special yearly DES exam for the rest of your life.

Annual DES exams can find clear-cell cancer early, so it can be treated. This cancer grows quickly and sometimes has no symptoms in the early stages. Typical treatment for clear-cell cancer may include a radical hysterectomy, surgical removal of all or part of the vagina, and reconstruction of the vagina. Radiation treatment may be added. 80 percent of women survive this cancer.

Studies show that DES daughters have a greater risk for a more common vaginal cancer, squamous cell carcinoma. You may also have adenosis—columnar cells where the usual squamous cells should be—around the cervix. If you do, you may be more vulnerable to precancerous or cancerous changes. Annual monitoring is recommended until any adenosis disappears; discuss this with your gynecologist and be sure she or he knows about your exposure.

Cervical dysplasia (abnormal cell change) is more common among DES daughters, but normal cell changes may be mistakenly seen as abnormal when your cervix is checked, leading to unnecessary treatment with possibly harmful effects. That’s why it’s important to find a healthcare provider with experience in DES screening.

Structural changes in the uterus and cervix are common in DES daughters. Cervical “collars” or “hoods” (adenosis) do not have to be treated and may disappear after age thirty. A smaller or T‑shaped uterus may contribute to pregnancy problems (see below).

If you are a DES daughter over age forty, your risk for breast cancer may be almost two times greater than that of unexposed women. DES mothers, too, have developed more breast cancers than unexposed women—sometimes as long as 20 years after exposure—so both mothers and daughters should get a clinical breast exam every year, in addition to doing self-exams to become familiar with the normal look and feel of their breasts. Women exposed to DES should report any changes to their health care provider. Annual mammography or other additional screening exams are also appropriate for DES daughters.

Contraception for DES daughters poses some special considerations. Birth control pills may be risky, since they increase estrogen exposure in someone already at higher risk of hormone-related cancer. IUDs may not be safe because of cervical and uterine abnormalities. Barrier methods (condom, diaphragm) are probably the safest choice overall.

Pregnancy problems have resulted from structural abnormalities in the uterus and cervix of DES daughters. You might have trouble conceiving, or be more likely to miscarry, deliver prematurely, or have an ectopic (tubal) pregnancy (in the fallopian tube instead of the uterus). A pregnant DES daughter needs high-risk obstetrical care. Checking early in pregnancy for signs of problems may help prevent serious complications.

The doctor [who] was doing my DES exams didn’t know anything about pregnancy problems for DES daughters. So I brought him seven articles that DES Action gave me. We both read them, and as a result, he checked my cervix at every prenatal visit. It took fifteen seconds and took away tons of anxiety.

Other problems, including endometriosis, menstrual irregularities, and pelvic inflammatory disease, have been reported by many DES daughters. DES sons have increased risk of urogenital problems. Recent studies have shown that DES granddaughters may have delayed menstruation regularity and DES grandsons may have an increased risk of hypospadias (in which the urethral opening on the penis is in the wrong place). Tell your doctor if you are a DES grandchild and be vigilant for any new information about DES.