Prenatal intervention for hydronephrosis.

PURPOSE: The widespread use of prenatal ultrasound results in an increased recognition of fetal hydronephrosis and technological advances now make fetal intervention possible. However, efficacy is unknown, and there have been errors in diagnosis, and associated morbidity and mortality. This review focuses on the current status of prenatal diagnosis and management of hydronephrosis.

MATERIALS AND METHODS: The relevant literature on prenatal physiology, prenatal diagnosis, experimental obstruction and clinical series of prenatal intervention was reviewed.

RESULTS: Prenatal ultrasound is a poor discriminator of physiological hydronephrosis, obstruction, renal dysplasia and reflux. Persistent early onset oligohydramnios is the best predictor of poor neonatal outcome. New minimally invasive techniques may aid diagnostically but they may not improve outcome. Dysplasia is often present by the time hydronephrosis is detected and it is not reversible in experimental models. Prenatal intervention is technically feasible but the survival rate is only 47%, and catheter placement and open fetal surgery have significant fetal and maternal risks. Complications occur in up to 45% of fetuses.

CONCLUSIONS: Prenatal intervention for hydronephrosis remains an experimental technique. The most important question is whether prenatal therapy for obstructive uropathy improves survival and decreases long-term morbidity and mortality in affected fetuses.