POSTNATAL ULTRASOUND AND CYSTOGRAPHY AFTE R THE PRENATAL-DIAGNOSIS OFMODERATE DILATATION OF THE RENAL PELVIS - A PROSPECTIVE-STUDY OF 89 CASES

We evaluated postnatal management after the prenatal diagnosis of mode rate dilatation of the renal pelvis (antero-posterior diameter superio r to 1 mm per month of pregnancy and inferior to 15 mm at full term). Eighty-nine neonates who had a moderate dilatation in utero were evalu ated by ultrasound and voiding cysto-urethrography. Ultrasound was per formed between day 2 and day 7 in 83 cases, after day 7 in 6 cases. Vo iding cysto-urethrography was performed during first month in 80 cases , after this period in 9 cases. Sixty-five neonates were shown to have a malformation of the urinary tract: reflux (n = 27), megaureter (n = 20), uretero-pelvic junction obstruction (n = 19), renal duplication (n = 7), posterior urethral valves (n = 2), horseshoe kidney (n = 1), ureteric cyst (n = 1). Reflux which is frequent in neonates with urina ry tract infection, is the most frequent cause of moderate dilatation of the fetal renal pelvis. Combination of ultrasound and voiding cysto -urethrography in neonates allows a quick, full diagnosis. It helps ra tionalize the use of prophylactic antibiotic treatment.