Prevalence of Undescended Testis in Tehran and the Main Risk Factors: A Cross-sectional Multicenter Study

 Undescended testis (UDT) is the most common abnormality of the male genital system. To date, no study has been carried out to determine the prevalence of UDT and its risk factors in Tehran. This study aimed to determine the frequency of cryptorchidism and its risk factors in male infants who were born at three university hospitals in Tehran.

 A cross-sectional study was done on boys born at three major university hospitals (Baharlou, Yas, and Ziaeian Hospitals) in Tehran between 2016 and 2018. All of the newborns were examined on the first or second day of birth. Demographic data were collected using hospital databases after getting permission. Also, the pregnancy care card was used to collect maternal complications of pregnancy, including gestational diabetes mellitus, preeclampsia, eclampsia, fetal malignancy, preterm, and late delivery.

 A total of 1,350 boys were evaluated. Eleven (0.81%) boys had UDT. There were statistically significant associations between UDT and maternal hypertension, presence of other congenital anomalies, infection during pregnancy, fetal presentation, and type of delivery. The average birth weight and gestational age were lower in patients with UDT than in healthy infants.

 The prevalence of UDT in Tehran was much lower than in previously reported rates in other areas. Factor analysis showed that cryptorchidism was associated with the markers of poor fetal development.