Nonobstructive fetal hydronephrosis: sonographic recognition and therapeutic implications.

The postnatal outcome of nine patients with the prenatal diagnosis of fetal hydronephrosis is reported. In only three of the nine cases was true obstructive hydronephrosis demonstrated, and in only one of these cases (11%) the patient might have benefited from decompressive surgery at the time of diagnosis of the abnormality. Twenty-nine additional cases from the literature are reviewed. It is concluded that a major deterrent to early fetal surgery is that most of the cases of obstructive hydronephrosis are identified too late in gestation.