Health care providers and researchers who work with pregnant women have known for years that women exposed to DES before birth (in the womb), known as DES Daughters, often have difficulty conceiving and carrying a pregnancy to full term. Although the reasons for increased pregnancy complications among DES Daughters are not fully understood, the researchers of this study hypothesized that structural abnormalities in the cervix may account for increased miscarriages. The researchers compared the pregnancy histories of 3,373 DES Daughters with those of 1,036 unexposed women; these women comprised the largest study of pregnancy among DES Daughters to date.

The researchers found that DES Daughters had more negative outcomes during first pregnancies than unexposed women. Of DES Daughters, 64% delivered a full-term baby during their first pregnancy compared with 85% of unexposed women. Approximately 20% of DES Daughters experienced a miscarriage compared with 10% of unexposed women. Ectopic (tubal) pregnancy occurred in 4%-7% of DES Daughters, but less than 1% of unexposed women experienced this problem.

When considering all pregnancies, DES Daughters suffered more reproductive complications than unexposed women. Approximately 84% of DES Daughters had delivered at least one live birth compared with 87% of unexposed women. Approximately 30% of DES Daughters experienced a miscarriage compared with 24% of unexposed women. Of DES Daughters, 7%-11% had ectopic pregnancies, whereas only 1.9% of unexposed women had such a pregnancy. Premature births and miscarriages during the second trimester of pregnancy were also more common among DES Daughters than among unexposed women. Approximately 25% of DES Daughters had never been pregnant compared with approximately 19% of unexposed women.

Although many DES Daughters are now beyond their childbearing years, many younger DES Daughters still plan to have children. DES Daughters and their health care providers should be aware that these women are at an increased risk for a range of pregnancy complications. Extensive prenatal care may be needed for a pregnant woman exposed to DES or a woman trying to become pregnant who knows she was exposed to DES.

Citation: Kaufman RH, Adam E, Hatch EE, Noller KL, Herbst AL, et al. Continued follow-up of pregnancy outcomes in diethylstilbestrol-exposed offspring. Obstet Gynecol 2000;96:483-9.