Cancer Risks Continue For Daughters of Women Who Took DES

by Christina Elston

A synthetic form of estrogen prescribed to millions of pregnant women decades ago tocancer cellprevent miscarriage and premature labor continues to cause cancer and other health risks to the daughters of those women today.

Doctors prescribed diethylstilbestrol – or DES – to pregnant women between 1940 and1971. But as babies exposed to DES in utero grew up, government studies found that daughters of these women were at increased risk for cancer, and use of the drug was halted.

Researchers have continued to follow many of the 5-10 million women and babies exposed to DES, and a study out (Oct. 6, 2011) from the National Cancer Institute and published in the New England Journal of Medicine details their risk of cancer, and birth and reproductive problems.

Among 6,500 women studied, researchers found that women exposed to DES while in the womb had increased risk of 12 separate medical conditions, including:

• Cancers

– 40 times greater risk of clear-cell adenocarcinoma, a rare cancer of the vagina (which still only impacts about 1 in 1,000 women exposed to DES);
– 2.3 times greater risk of pre-cancerous cells in the cervix or vagina (cervical intraepithelial neoplasia); and
– 1.8 times greater risk of breast cancer.

• Birth problems

– 8 times greater risk of neonatal death;
– 4.7 times greater risk of pre-term delivery;
– 3.8 times greater risk of second-trimester miscarriage;
– 2.4 times greater risk of stillbirth;
– 1.6 times greater risk of first-trimester miscarriage; and
– 1.4 times greater risk of preeclampsia.

• Other reproductive issues

– 3.7 times greater risk of ectopic pregnancy, where the fetus implants outside the uterus;
– 2.4 times greater risk of infertility; and
– 2.4 times greater risk of early menopause.

As these “DES daughters” enter their 40s and beyond, the study has found that some of their risks increase. Their chance of developing breast cancer after age 40 is 80 percent higher than that in women not exposed to DES, and by age 55, 1 in 25 of these DES-exposed women will develop potentially pre-cancerous cells in the cervix or vagina, and 1 in 50 will develop breast cancer.
Other research has shown that sons of mothers treated with DES also face health risks, including increased risk for some testicular abnormalities. And researchers are now looking at possible health effects on the grandchildren of mothers who took DES during pregnancy.
For now, the advice for women exposed to in utero is to tell your doctor and undergo thorough annual pelvic and breast examinations, including pap tests and mammograms as recommended.
For more information on DES exposure and its risks, visit

Christina Elston, Health Editor

Posted October 2011