Objective: To examine prenatal diethylstilbestrol (DES) exposure in relation to male reproductive outcomes.
Design: Prospective observational study.
Setting: Participants were identified through record review, clinical trial participation, or an obstetrics clinic.
Patient(s): A total of 1,085 DES-exposed and 1,047 unexposed men.
Intervention(s): Participants were exposed prenatally to DES through the mother's obstetrics care or clinical trial participation.
Main outcome measure(s): Infertility; never fathering a pregnancy or live birth; number of pregnancies or live births fathered.
Result(s): We found little evidence that prenatal DES exposure affects the likelihood of never fathering a pregnancy or live birth, or influences the mean number of fathered pregnancies or live births. Our data suggest that DES-exposed men are slightly more likely to experience infertility (relative risk [RR] = 1.3, 95% confidence interval [CI] = 1.0-1.6). The DES dose and gestational timing did not influence infertility or the number of pregnancies or live births fathered, but results were inconsistent for dose effects on the likelihood of never fathering a pregnancy or a live birth.
Conclusion(s): Prenatal DES exposure may be associated with a slightly increased risk of having an infertility experience, but does not increase the likelihood of never fathering a pregnancy or a live birth, or the number of pregnancies or live births fathered.