Fetal vesicoureteral reflux: neonatal findings and follow-up study

To examine features of primary vesicoureteric reflux (VUR) at birth following prenatal hydronephrosis and to describe the course of congenital damage in the first two years of life. We reviewed the records of 382 patients with prenatally diagnosed dilated urinary tracts seen during a 15-years period. When fetal hydronephrosis was confirmed at birth, voiding cystography was performed. If a VUR was diagnosed dimercaptosuccinic acid (DMSA) renography, at 1 month of age, was also performed. Cystography and DMSA renography were repeated and 1 and 2 years of age. Of 382 patients with prenatal hydronephrosis, 68 (17.8%) had primary VUR (50 male and 18 female, M:F = 3:1). VUR was unilateral in 24 patients and bilateral in 44 for a total of 112 refluxing renal units (RRUs). High-grade VUR (grade > or = 4) was found in 70 (62.5%) RRUs, and 60 (85.7%) were boys. Grade V reflux was observed in 96.5% of males. At birth, 22 (20%) RRUs had moderate impairment of renal function. In 12 (10%) RRUs (grade > or = 4) was demonstrated by a severe decrease in renal function. In all cases no focal scarring was noted. Eight infants (all males), with grade 5 degrees VUR, in the first six months of life had surgical treatment. The majority of the RRUs (110/112 = 89%) were followed medically. Mild reflux (grade I-III) had resolved in 81% RRUs, severe reflux (grade > or = 4) had resolved in 38% RRUs. Serial renal scans during the follow-up showed no progression of renal damage. VUR diagnosed at birth on prenatal ultrasonography is associated with congenital damage, with males affected more often than females. In patients without infection, after two years, modification of renal function or renal scars are very rarely observed.