The story of diethylstilbestrol (DES) is a cautionary tale. This synthetic estrogen was prescribed from the 1940s through the 1960s to help pregnant women avoid miscarriage and premature delivery. Not only did it fail to work, but it also created health problems for at least two generations. The lingering effects of DES mean that those exposed to the medication still need to take precautions, reports the May 2010 issue of Harvard Women’s Health Watch.

In 1971, the FDA warned doctors to stop prescribing DES after it was linked to a rare cancer of the vagina and cervix in the daughters of women who took the drug while pregnant. Many studies since then have confirmed links between DES exposure and various health risks. Since 1992, with the DES Follow-up Study, the National Cancer Institute has been monitoring women who took DES and their daughters and sons who were exposed to it in the womb.

Harvard Women’s Health Watch outlines what we’ve learned about these health risks and the precautions DES-exposed women and men should take:

Women who took DES have a moderately increased risk of breast cancer (a one-in-six lifetime risk, versus a one-in-eight lifetime risk for women who didn't take DES). They should have annual clinical breast exams and regular mammograms, do breast self-exams, and tell their doctors about their exposure.

Daughters of women who took DES have a 40-fold increased risk of clear cell adenocarcinoma of the vagina and cervix, a rare form of cancer. DES daughters are 2.5 times more likely to develop breast cancer after age 40. DES exposure is also associated with several reproductive anatomical irregularities. DES daughters should make sure their clinicians know they were exposed to the medication, have yearly gynecological exams and Pap testing, and follow standard guidelines for mammography screening.

Sons of women who took DES have an increased risk of noncancerous growths on the testicles. No special screening exams or tests are currently recommended, but DES sons should tell their clinicians about their exposure.

Read the full-length article: "What are the health risks for DES daughters and their children?"