OBJECTIVECryptorchidism is the most common urogenital congenital malformations in males, which increases male infertility and testicular tumors. It is necessary to identify its risk factors.

METHODSA hospital-based case-control study was conducted. Cases were 99 boys with cryptorchidism with two matched controls per case were randomly selected. Both cases and controls were interviewed with a uniformed questionnaire by face to face. Conditional logistic regression model was used for univariable and multivariate analysis by SAS6.12 computer software was used to estimate odds ratios (OR) and their 95 per cent confidence internals (95% CI).

RESULTSMultiple conditional logistic regression analysis showed that cryptorchidism was positively associated with maternal common cold accompanied fever in the first trimester (OR = 9.37, 95% CI: 2.25 - 39.09), with threatened abortion in the first and/or second trimester (OR = 4.66, 95% CI: 2.02 - 10.74), maternal preeclampsia during pregnancy (OR = 16.33, 95% CI: 1.40 - 191.20), paternal exposure to pesticides occupationally (OR = 12.79, 95% CI: 2.90 - 56.43), neonatal low birth weight (OR = 5.77, 95% CI: 1.39 - 23.98), and maternal age under 24 years (OR = 2.89, 95% CI: 1.29 - 4.06).

CONCLUSIONSThe risk factors of cryptorchidism were maternal common cold accompanied fever in the first trimester, threatened abortion in the first and/or second trimester, maternal preeclampsia during pregnancy, paternal exposure to pesticides occupationally, neonatal low birth weight, maternal age under 24 years.