Postnatal evaluation and outcome of infants with antenatal hydronephrosis.

This study was aimed at evaluating the clinical outcome of infants with antenatally diagnosed hydronephrosis. Our objective was also to determine whether there is a significant correlation between anterior posterior pelvic diameter (APPD) and urinary tract abnormalities detected. We retrospectively analyzed data of 145 infants collected between January 2000 and May 2010. Inclusion criteria were the presence of APPD > or = 5 mm on prenatal US scan after 20 weeks of gestation, at least 6-month follow-up and at least two postnatal US scans. Most patients underwent renal scintigraphy (n = 140, 96.6%) and micturating cystourethrography (n = 141, 97.2%). Of 145 infants, 77 (53.1%) had idiopathic or transient hydronephrosis. The second most common diagnosis was vesicoureteral reflux found in 21 (14.4%) infants, followed by ureteropelvic junction obstruction without significant kidney damage found in 18 (12.4%) infants. The relative risk of significant urologic abnormality according to the degree of antenatal hydronephrosis (ANH) was 21.25 (95% CI: 2.95-156.49) for severe ANH, 1.57 (95% CI: 0.94-2.62) for moderate ANH and 0.47 (95% CI: 0.33-0.66) for mild ANH. There was a significant increase in the riskper increasing degree of hydronephrosis. In 19 out of 145 (13.2%) infants, immediate surgery was required. These data support the need of antenatal detection and long-term postnatal follow-up of infants with ANH.