Natural history of obstructed and pseudo-obstructed megaureters detected by prenatal ultrasonography.

In a series of 38 patients with non-refluxing megaureters detected by prenatal ultrasonography, 89% were males and 16% had associated ipsilateral or contralateral urinary anomalies. By renographic criteria, 36% of ureters were not obstructed; renal function was never impaired initially and, on follow-up, spontaneous resolution of dilatation was common. Infective urinary calculi developed in 3 of the boys. In ureters obstructed by renographic or pressure-perfusion criteria, 79% exhibited normal renal function initially. Most such patients were managed expectantly; on follow-up, functional deterioration occurred in 2 patients, while in the remainder dilatation usually persists but without change in function.