Is screening for vesicoureteral reflux mandatory in infants with antenatal renal pelvis dilatation?

To determine whether postnatal ultrasound (US) can guide the use of voiding cystourethrography (VCUG) in infants with antenatally detected renal pelvis dilatation (ARPD).

14,000 pregnant women consecutively underwent routine US examination during the second trimester. US examinations later in pregnancy were performed as follow-up of previous anomalies or on obstetrical indications. One hundred and six fetuses with ARPD > or =5 mm were identified. Two postnatal US examinations were performed in the newborns: on the 5th to 7th day and during the 3rd week of life. The findings were considered normal when renal pelvis dilatation (RPD) was < or =7 mm on both US examinations, and no calyceal or ureteric dilatation or signs of renal dysplasia or other anomalies were present. VCUG was done 6 to 8 wk after birth.

In 53 of 103 analysable infants, the postnatal ultrasonographic findings were normal. The VCUG was abnormal in three of these 53 infants, all with vesicoureteral reflux (VUR) grade I. Of 50 infants who had abnormal US examinations, six had VUR, four of which were grade IV and V reflux.

In infants with ARPD who undergo two postnatal US examinations with RPD < or =7 mm and have no other abnormalities, VCUG is unnecessary.