Hypospadias in Washington State: Maternal risk factors and prevalence trends

Objective. Maternal risk factors for hypospadias are poorly defined, and there is debate about temporal trends in hypospadias prevalence. We examined select maternal characteristics as possible risk factors for hypospadias among male offspring and evaluated yearly prevalence rates in Washington State. Methods. We performed a population-based, case-control study using linked birth-hospital discharge data from Washington State for 1987 - 1997 and prevalence data for 1987 - 2002. All cases of hypospadias were identified on the basis of International Classification of Diseases, Ninth Revision, codes from the birth hospitalization (N = 2155). Five control subjects were randomly selected for each case subject from the remaining singleton births, frequency matched according to year of birth ( N = 10 775). Maternal and infant characteristics were ascertained from the birth certificate. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Yearly prevalence was determined by dividing the total number of hypospadias cases by the number of male singleton live births for each year. Results. The risk of delivering an affected male infant increased with advancing maternal age; relative to women < 20 years of age, those > 40 years of age were at greatest risk ( OR: 1.70; 95% CI: 1.17 - 2.48). Infants of nonwhite women were generally at decreased risk. Infants born to women with preexisting diabetes mellitus were at greater risk than those born to women without diabetes (OR: 2.18; 95% CI: 1.03 - 4.60); however, this was not observed for infants born to women with gestational diabetes. The birth prevalence of hypospadias in 2002 was 5.0 cases per 1000 male births, not significantly different from that in 1987. Conclusion. Older maternal age, white race, and preexisting diabetes were associated with increased risk of hypospadias among male offspring. The prevalence of hypospadias in Washington State did not increase significantly between 1987 and 2002.