[Fetal hydronephrosis. Case report and literature review].

Fetal hydronephrosis is the most common congenital anomaly detected by routine prenatal ultrasound. It is the abnormal dilatation of the urinary canal, and its most frequent causes are physiologic and transitory hydronephrosis, with spontaneous resolution. Pelvi-ureteric junction obstruction represents its first pathological cause. Renal function worsening is its major complication. During pre and post-natal periods ultrasound is the election diagnostic method for this entity. The two most accepted criteria to defining hydronephrosis are Society for Fetal Urology grade and anterior-posterior diameter of renal pelvis. Here we present a case of unilateral fetal hydronephrosis detected at 31" gestational week, its pre and postnatal ultrasound control, and obstetric and neonatal treatment. Prenatal opportune diagnosis and adequate postnatal treatment (medical or surgical) are very important to preserve renal function.