Can we predict which cryptorchidism will descend? A cohort study in 976 Korean neonates

To evaluate the incidence and perinatal risk factors associated with undescended testis (UDT) in neonates and to identify predictors of persistent UDT at 6 months of age.

This retrospective cohort study included 976 male neonates born at Chonnam National University Hospital between 2018 and 2023. Clinical variables included birth weight, gestational age, Apgar score, delivery mode, urogenital anomalies, maternal age, estrogen exposure, and family history. UDT was diagnosed at birth, and spontaneous descent was assessed at 6 months. Logistic regression identified significant predictors.

UDT incidence was 8.8% (86/976), significantly higher in preterm than term infants (28.1% vs. 3.1%, p<0.001). Low birth weight (odds ratio [OR] 3.82, p<0.001), prematurity (OR 2.75, p=0.001), maternal estrogen exposure (OR 2.57, p=0.006), and urogenital anomalies (OR 2.13, p=0.026) were independent predictors of UDT at birth. Among infants with UDT, 72.1% showed spontaneous descent by 6 months. Urogenital anomalies were associated with a lower likelihood of spontaneous descent (OR 0.32, p=0.028), whereas prematurity, low birth weight, and maternal estrogen exposure increased the likelihood of descent.

UDT is relatively common in Korean neonates, particularly among preterm infants. While most cases resolve spontaneously within 6 months, infants with urogenital anomalies are less likely to descend spontaneously and may need closer follow-up and earlier surgical consideration. Early perinatal characteristics may help stratify the risk of persistent UDT and guide clinical decision-making.