Management of fetal hydronephrosis.

Prenatally detected hydronephrosis has become a common diagnosis for both pediatric nephrologists and urologists. Hydronephrosis is most commonly assessed by the Society for Fetal Urology grading system or anterior-posterior diameter of the renal pelvis in the transverse plane. Some cases of bilateral obstruction, most commonly from posterior urethral valves, can be life-threatening and require close monitoring or, occasionally, fetal intervention. The majority are unilateral and of no threat to the growing fetus. The crux of postnatal management is the separation of the minority of patients whose renal function is at risk from the majority who will suffer no renal consequences. This management involves a regimen of ultrasounds, voiding cystourethrograms, and nuclear renograms for diagnosis and surveillance. Recent literature has been aimed at the timing and necessity of these studies in order to minimize extraneous studies without compromising renal function.