Outcomes of children with isolated antenatal hydronephrosis

Background: Antenatal hydronephrosis (ANH) is one of the most common abnormalities detected during prenatal ultrasound. There is significant variability in the postnatal management of ANH. Our objective was to report the outcomes of patients with ANH, spontaneous resolution rates, surgical intervention rates, and factors contributing to these parameters.

Methods: A total of 227 patients and 264 renal units with ANH were included in this study. We used the renal pelvis anteroposterior diameter and the Society for Fetal Urology grading system to classify and compare ANH as mild, moderate, and severe.

Results: The patients' median follow-up period was 48 months (with a minimum of 6 months and a maximum of 136 months). Of the 264 renal units, 123 (46.6%) had mild, 101 (38.26%) had moderate, and 40 (15.15%) had severe antenatal hydronephrosis. The spontaneous resolution rate was 91.9% in the mild hydronephrosis group (n = 113), 81.2% (n = 82) in the moderate hydronephrosis group, and 37.5% (n = 15) in the severe hydronephrosis group. The patients with higher hydronephrosis grades required a longer time to resolve. Only one patient with a posterior urethral valve had reduced estimated glomerular filtration. None of the patients had proteinuria or hypertension.

Conclusion: Although the outcome of the patients with mild hydronephrosis was excellent, there was a progression of the disease, especially within the first 6 months, and 6% of our cases required surgical intervention. Additional prospective studies are needed to define the risk of urinary tract abnormalities with any degree of ANH.