Time to pregnancy and secondary sex ratio in men exposed prenatally to diethylstilbestrol

Little is known about the influence of prenatal diethylstilbestrol (DES) exposure on time to pregnancy or secondary sex ratio in men. The authors evaluated these associations among men participating in the DES Combined Cohort Follow-up Study for whom exposure status was confirmed by medical record. In 2001, men provided data on their reproductive histories. Demographic, behavioral, and medical data were collected in 1994, 1997, and 2001. Cox's proportional hazards models with frailty were used to estimate fecundability ratios for time to pregnancy in relation to DES. Generalized estimating equations were used to estimate odds ratios for fathering a male birth in relation to DES. Models included potential confounders and accounted for multiple pregnancies contributed by each man. Overall, DES was not associated with a delay in time to pregnancy (fecundability ratio = 0.95, 95% confidence interval: 0.86, 1.06). The odds ratio for fathering a male birth was 0.92 (95% confidence interval: 0.80, 1.04) comparing the exposed with the unexposed. In conclusion, prenatal DES exposure was not associated with a significant decrease in either fecundability or secondary sex ratio.