Antenatal diagnosis of renal tract anomalies by ultrasound.

A first group of 141 pregnant women carrying children at risk of a renal tract anomaly, because of a positive family history was referred to our obstetrical ultrasound department. Prenatal ultrasound examination revealed an abnormality of the urinary tract in 8%. A recurrence was observed under the following conditions: renal agenesis, multicystic kidney and urethral obstruction, but not in ureteral obstruction. In two children renal abnormalities were not detected until after birth, one child having an autosomal recessive and the other an autosomal dominant form of polycystic kidney disease. The large variation in the prenatal manifestation of cystic kidney disorders requires that predictions of possible recurrence on the basis of repeated ultrasound examinations should be made with great care. A second group of 98 pregnant women was referred because of a suspected renal abnormality found by ultrasound in the absence of a previous family history. In 64% a malformation of the urinary tract was confirmed (31 with obstructive uropathy and 32 with cystic kidneys). In almost half of the cases with subvesical obstruction or with cystic kidney disease a structural defect of extrarenal organs was present.