Short Term Outcome of Antenatal Hydronephrosis: A Single Center Experience

Background Fetal hydronephrosis is a common urinary tract anomaly that may result in renal parenchyma damage. Ultrasound is considered a simple, noninvasive procedure to diagnose and track antenatal hydronephrosis. Our aim was to study the clinical course of fetal hydronephrosis in fetuses. Materials and Methods In this prospective study, 60 fetuses in Imam Reza Hospital in Kermanshah, Iran, which were diagnosed with prenatal hydronephrosis in the third trimester of pregnancy, were grouped into three categories according to the anteroposterior diameter of the renal pelvis: mild (7-9 mm), moderate (9-15 mm), and severe (> 15 mm). The groups were followed for two months after birth with ultrasonography to investigate the clinical course and spontaneous resolution.   Results: The severity of the left-side hydronephrosis at the antenatal ultrasound was mild in 27 (45%), moderate in 19 (31.7%), and severe in 3 (18.30%) fetuses. At the follow-up, 30 patients had normal renal pelvis. Severe hydronephrosis, however, remained in three patients after 6 to 8 weeks of follow-up. The severity of the right-side hydronephrosis at the antenatal ultrasound was mild in 15 (25%), moderate in 10 (16.7%), and severe in 1 (1.7%) fetuses. At six to eight weeks after birth, 15 patients had normal renal pelvis. In 10 patients (16.7%), improvement in hydronephrosis was observed after 6-8 weeks. In the first evaluation, 45 patients (75%) had unilateral hydronephrosis and 15 patients (25%) had bilateral hydronephrosis. After six to eight weeks, these decreased to 22 (36.7%), and 6 (10%) cases, respectively. Conclusion The use of antenatal and postnatal ultrasound for imaging follow-up of neonates with fetal hydronephrosis showed that a significant number of cases improved after 6-8 weeks.