Association between Severity and Etiology of Antenatal Hydronephrosis in Neonates

Abstract

Background and Aim: Antenatal hydronephrosis refers to the dilation of renal pelvis during fetal development. This condition is commonly diagnosed during intrauterine ultrasonography. According to available statistics, fetal anomalies are seen in about 0.5-2.5% of intrauterine ultrasound examinations. The most common anomaly is hydronephrosis. The severity of renal pelvic dilatation in the first sonography after birth may help to diagnose the underlying cause of antenatal hydronephrosis. On the other hand, knowledge of the etiology of hydronephrosis can help to understand the clinical course of the disease and to determine an appropriate therapeutic protocol for patients.Methods: In this descriptive cross-sectional study, all infants with antenatal hydronephrosis referred to the pediatric nephrology clinic of Imam Khomeini Hospital, Ilam, Iran were evaluated. Considering a hydronephrosis frequency of 50%, confidence interval of 95%, and error rate of 13%, the sample size was calculated at 60 subjects.Results: This study was performed in 61 neonates with antenatal hydronephrosis, including 43 (70.5%) males and 18 (29.5%) females. The frequency of hydronephrosis was significantly higher in boys than girls. Non-obstructive hydronephrosis was the most common underlying etiology in the patients. Most of the infants had a mild hydronephrosis. UPJO (ureteropelvic junction obstruction) was the most common cause of hydronephrosis. Furthermore, most of the patients had bilateral hydronephrosis.Conclusion: Non-obstructive hydronephrosis accounted for about 50% of antenatal hydronephrosis cases in this study. The intensity of the pelvic dilatation was directly associated with obstructive hydronephrosis, which can be used as a diagnostic guide. Keywords: Hydronephrosis; Etiology; Neonates; Severity.