Maternal use of oral contraceptives during early pregnancy and risk of hypospadias in male offspring.

OBJECTIVES

To examine the association between maternal use of oral contraceptives in early pregnancy and increased prevalence of hypospadias in male offspring.

METHODS

We conducted a nationwide population-based case-control study using data from nationwide medical databases. Among live male births between January 1, 1996, and December 31, 2005, we identified all cases of hypospadias recorded anytime postpartum (n = 1683) and randomly selected 10 controls per case without such a diagnosis (n = 15 650), matched by year and hospital of birth. We used conditional logistic regression to estimate prevalence ratios stratified according to time of diagnosis (within 6 months postpartum, >6 months postpartum), controlling for potential confounding factors including maternal age, birth order, maternal smoking, prescriptions for ovulation-inducing drugs, antiepileptics, and antidiabetics, and a maternal diagnosis of pre-eclampsia.

RESULTS

We included 1683 cases of hypospadias and 15,650 population controls during 1996-2005. Among the 1186 boys who had their hypospadias diagnosis recorded within 6 months postpartum, 28 (2.4%) had been exposed to oral contraceptives between 30 days before conception until the end of the first trimester. Among the controls, 307 (2.8%) were similarly exposed, corresponding to a prevalence ratio of 0.85 (95% CI: 0.57-1.27) after adjusting for possible confounders. For a diagnosis registered >6 months postpartum, the adjusted prevalence ratio was 1.12 (95% CI: 0.61-2.06).

CONCLUSIONS

Our data do not support the hypothesis that maternal use of oral contraceptives around conception is associated with an increased prevalence of hypospadias in the offspring.