August 26, 2011

Diethylstilbestrol (DES) is a synthetic form of estrogen, which was prescribed to millions of women from 1940 to 1971. It was thought to prevent miscarriage and ensure a healthy pregnancy. Its use declined in the 1960s after studies showed that it was not effective in preventing the complications of pregnancy that it was prescribed for. It was also found that when given during the first five months of pregnancy, DES can interfere with the development of the reproductive system in a fetus. The females whose mothers took DES while pregnant are referred to as “DES daughters.”

While there may be no obvious signs of DES exposure, there are health risks. All DES daughters have a risk of about 1 in 1,000 for a rare cancer of the vagina or cervix called clear cell adenocarcinoma. It usually occurs after age 14, with most cases found at age 19 or 20. Some cases have been reported by women in their 30s or 40s. This cancer is practically nonexistent in nonDES-exposed women.

A link has been found between diethylstilbestrol exposure in utero and an increased risk of developing abnormal cells in the tissue of the cervix and vagina. Terms used to describe this condition are dysplasia, cervical intraepithelial neoplasia (CIN), and squamous intraepithelial lesions (SIL). Although these abnormal cells resemble cancer cells in appearance, they do not invade nearby healthy tissue as cancer cells do. These abnormal cellular changes usually occur between the ages of 25 and 35, but may appear at other ages as well. Although this condition is not cancer, it may develop into cancer if left untreated.

Diethylstilbestrol daughters are at increased risk of infertility, ectopic pregnancy, miscarriage, and preterm labor and delivery. DES daughters have an increased incidence of structural changes in the vagina, uterus, or cervix, which may or may not be linked to pregnancy problems. Most DES daughters can become pregnant and carry their babies to term, but because of the known risks, they require high-risk obstetric care and early confirmation of pregnancy.

Women exposed to diethylstilbestrol may also need to consider appropriate contraception. Although studies have not shown that the use of birth control pills or hormone replacement therapy is unsafe for diethylstilbestrol daughters, some doctors believe these women should avoid these medications. Structural changes in the vagina or cervix should cause no problems with the use of diaphragms or spermicides.

Women who used diethylstilbestrol may have a slightly increased risk of breast cancer. DES mothers should practice monthly breast self-exams, have regular breast cancer screening, and yearly medical checkups that include a pelvic examination and a Pap test.

There is some evidence that DES-exposed sons may have testicular abnormalities, such as cysts on the ducts behind the testicle, undescended testicles, or abnormally small testicles. The risk for testicular or prostate cancer is unclear. A diethylstilbestrol son should practice regular testicular self-exams and inform his physician of his exposure and be examined periodically.

Researchers continue to study DES exposure as daughters move into the menopausal years. The cancer risks for exposed daughters and sons are being studied to determine if they differ from the unexposed population.

In addition, researchers are studying possible health effects on the grandchildren of mothers who were exposed to DES during pregnancy. They are referred to as third-generation daughters or DES granddaughters. There are two published studies. One done in 1995 found that the age menstruation began was not affected by the mother’s exposure to DES. A 2002 study concluded that third-generation effects of in utero DES exposure are unlikely.

Individuals born between 1940 and 1971 should ask their mothers or other relatives who might know of the mother’s pregnancy history if she took any medication during her pregnancy, or if she had any problems during her pregnancy. If a woman used DES while pregnant, it is advisable that she tell her children about her DES exposure. Even if they have not had health problems, they need to know so they can get the health care they may need now or in the future. The need for an annual pelvic exam is critical and is slightly different from a routine exam.

For a list of resources including books, support groups, organizations, and attorneys see DES Action USA (510-465-4011;; www.

SEE ALSO: Cancer, Cervical cancer, Miscarriage, Pregnancy


Category: D