Prenatal diagnosis of primary megaureter

22 of 114 infants with prenatal diagnosis of urinary tract malformations (15 boys) had obstruction of the ureterovesical junction caused by primary megaureter (n = 14), ureterocele (n = 7), or ectopic ureter (n = 1). Infants with infravesical obstruction or refluxing systems were excluded. All infants had a normal renal function and probably only 5 of them (23%) would have been diagnosed during infancy without prenatal diagnosis. A total number of 26 renal units was evaluated. Six infants had ipsilateral duplication with additional contralateral duplication (n = 2) or vesicoureteric reflux (n = 2). A nonfunctioning kidney or upper pole of duplication was noted in 7 units (5 with ureteroceles); in two instances a moderately dysplastic kidney was present. One boy with urinary infections developed renal scarring during follow-up. Conservative treatment was performed in 14 renal units while 12 units of 11 children had 22 operations (9 temporary diversions) at a mean age of 4,6 months. A severe operative complication was noted in one infant. Conservative treatment is justified in many infants with primary obstructive megaureters but severe renal dysplasia may be present even neonatally. Yet we feel that prenatal diagnosis benefitted most infants, especially those with the most severe malformations.