Continued follow-up of pregnancy outcomes in diethylstilbestrol-exposed offspring.

OBJECTIVE To evaluate long-term pregnancy experiences of women exposed to diethylstilbestrol (DES) in utero compared with unexposed women. METHODS This study was based on diethylstilbestrol-exposed daughters, the National Collaborative Diethylstylbistrol Adenosis cohort and the Chicago cohort, and their respective nonexposed comparison groups. Subjects who could be traced were sent a detailed questionnaire in 1994 that contained questions on health history, including information on pregnancies and their outcomes. We reviewed 3373 questionnaires from exposed daughters and 1036 questionnaires from unexposed women. RESULTS The response rate was 88% among exposed and unexposed women. Diethylstilbestrol-exposed women were less likely than unexposed women to have had full-term live births and more likely to have had premature births, spontaneous pregnancy losses, or ectopic pregnancies. Full-term infants were delivered in the first pregnancies of 84.5% of unexposed women compared with 64. 1% of exposed women identified by record review (relative risk [RR] 0.76, confidence interval [CI] 0.72, 0.80). Preterm delivery of first births occurred in 4.1% of unexposed compared with 11.5% of exposed women, and ectopic pregnancies in 0.77% of unexposed compared with 4.2% of exposed women. Spontaneous abortion was reported in 19.2% of DES-exposed women compared with 10.3% in control women (RR 2.00, CI 1.54, 2.60). According to complete pregnancy histories (many women had more than one pregnancy), preterm births were more common in DES-exposed women (19.4% exposed versus 7.5% unexposed (RR 2.93 CI 2.23, 3.86). Second-trimester spontaneous pregnancy losses were more common in DES-exposed women (6.3% versus 1.6%; RR 4.25, CI 2.36, 7.66). More first-trimester spontaneous abortions occurred in DES-exposed women than in controls (RR 1.31, CI 1.13, 1.53), and DES-exposed women had at least one ectopic pregnancy more often than unexposed women (RR 3.84, CI 2.26, 6.54). CONCLUSION Pregnancy outcomes in DES-exposed women were worse than those in unexposed women.