Approach to the foetus with congenital hydronephrosis.

Recent technological advances in prenatal ultrasonography have been responsible for the detection of a variety of congenital abnormalities in utero. The widespread use of this study during pregnancy has led to an increased recognition of foetal hydronephrosis. It has been postulated that unrelieved, high-grade urinary obstruction in utero may produce progressive renal damage. This supposition has resulted in the development of techniques for foetal intervention in attempts to correct obstructive uropathy and arrest renal dysplasia. Herein we review the techniques for assessment of foetal renal function and treatment options available for the foetus with hydronephrosis in utero. Most foetuses with hydronephrosis have dilated, low pressure systems with adequate urinary output and amniotic fluid volume and can be followed safely to term delivery. The accumulated experience to date indicates that the foetus with congenital hydronephrosis detected in utero should be managed expectantly with serial ultrasound examinations after delivery to establish an accurate diagnosis and to evaluate the status of the contralateral kidney. Functional tests after birth, such as renal scans and excretory urography, are mandatory to establish the proper diagnosis and assess the need for operative intervention.