Anatomical Disorders of Urinary System in Neonates with Prenatal Hydronephrosis

Background: Among urinary tract anomalies, hydronephrosis is particularly important, so it is the most common congenital defect that is detected in a pregnancy ultrasound. The causes of hydronephrosis are varying from transient to severe disorders. This study aimed to evaluate the types of anatomical disorders of the urinary system in neonates with a history of prenatal hydronephrosis. Methods: In this cross-sectional study, 40 neonates with prenatal hydronephrosis were examined. In infants with severe bilateral hydronephrosis, posterior urethral valve (PUV) in male fetus, dilated bladder, and trabeculae, ultrasound was performed as soon as possible, and in the rest of the infants in 3-7 days. In cases of mild hydronephrosis, the infant was followed, and in moderate and severe cases voiding cystourethrogram (VCUG) was performed in 6-8 weeks. In the absence of vesicoureteral reflux (VUR), a diethylenetriamine pentaacetate (DTPA) scan was performed to exclude obstructive uropathy. The data was analyzed through SPSS 26, using Fisher's exact test and repeated measures ANOVA. Results: Among 40 neonates (33 boys), the prevalence of anatomical disorders of the urinary system was 77.5%, and Ureteropelvic Junction Obstruction (UPJO) was the most frequent one with 54.8%. In infants with UPJO disorder, the mean anterior-posterior diameter (APD) of the pelvis increased significantly from the second trimester to infancy (p<0.001). Conclusion: The risk of adverse postnatal outcomes is significantly increased by the degree of prenatal hydronephrosis. Prenatal pelvic APD and associated urinary tract abnormalities can predict significant neonatal nephropathy and the need for postpartum surgery. Prenatal consultation with a pediatric nephrologist and urologist is helpful in reducing parental anxiety and facilitating postpartum management.