No increases in the rate of undescended testis in Hungary during the last 50 years: A population-based study.

Undescended testis (cryptorchidism) is a common structural birth defect, i.e. congenital abnormality of the male genital organs and increasing trend in its birth prevalence was reported in some countries. The aim of this study was to analyze the recorded annual birth prevalence of isolated undescended testis (IUT) in the population-based large dataset of the Hungarian Congenital Abnormality Registry for the period between 1962 and 2011, i.e. during the last 50 years. Cases with IUT reported after births were evaluated, and their annual rate per 1000 live-births was calculated. The rates of cases with IUT were compared with the so-called true rate of IUT measured in a previous clinical-epidemiological study based on the personal examination of 10,203 newborn infants. The birth prevalence of cases with recorded IUT in Hungary was lower than expected based on the true rate of IUT. Thus the two waves in the rate of IUT were connected with the different completeness of reporting. In conclusion the birth prevalence of cases with IUT in Hungary did not indicate a real increasing trend during the last 50 years.