Outcome of 116 moderate renal pelvis dilatations at prenatal ultrasonography.

To determine the incidence of urinary tract abnormalities detected in the presence of moderate fetal renal pelvis dilatation, we followed up pre- and postnatally 116 fetuses and children between 1985 and 1995. At prenatal ultrasound, 50 (43%) fetuses showed regressive dilatations, 57 (49%) a stable pattern, and 9 (8%) an evolutive pattern. In the presence of an evolutive dilatation, urinary tract obstruction was present in 8 cases. When a stable pattern was observed, i.e., a patent uropathy was present, surgical correction was performed in 27 of 53 (51%) cases. Regarding the postnatal evolution of 50 prenatal regressive moderate dilatations, we observed in 12 of 50 (24%) vesicoureteric reflux, of which 5 (10%) required surgical correction, and it is concluded that careful and extensive follow-up is mandatory.