ANTENATAL DIAGNOSIS OF CONGENITAL RENAL MALFORMATIONS USING ULTRASOUND

Our objectives were to determine the accuracy of antenatal sonography for the detection of congenital renal malformations and to characteriz e the type of malformations, seen in a 3-year prospective study at a u niversity-affiliate maternity hospital. Participants were 31 217 pregn ant women, during the study period, and subjects were 65 fetuses in wh om renal malformations were detected on antenatal ultrasound. Pelvic u ltrasound scans were performed at least once between 20 and 37 weeks' gestation on all pregnant women attending the antenatal clinic of the hospital for the detection of renal malformations. Fetal urinary sampl ing, diversion procedures, or termination of pregnancy were carried ou t as required in those detected to have renal anomalies. Postnatal dia gnosis was confirmed by sonography or autopsy. Diagnostic procedures a nd renal surgery were performed postnatally if indicated. Sixty-five f etuses (0.2 per cent) were diagnosed to have congenital renal malforma tion antenatally at a mean gestational age of 28.4 weeks. A dilated ur inary system was seen in 39, cystic renal disease in 15, agenesis/hypo plasia in six, combined lesions in four, and a horseshoe kidney in one . Oligohydramnios was noted in 20 (31 per cent) pregnancies. Multiple congenital malformations associated with renal anomalies were detected in 12 pregnancies. Termination was carried out at 20 weeks in two pre gnancies for lethal malformations; fetal urinary sampling was done in two fetuses with obstructed uropathy, and a vesicoamniotic shunt inser ted in one. Postnatal ultrasound confirmed a dilated urinary system in 32, cystic renal dysplasia in 15, renal aplasia/hypoplasia in five, c ombined lesions in six, and a horseshoe and an ectopic kidney in one e ach. Five infants were found to be normal. There were seven stillbirth s and seven neonatal deaths. Radionuclide scans showed obstruction in nine, decreased renal function in six, and absent renal functions in 1 0 infants. Micturating cystourethrography demonstrated reflux in 11 an d a non-refluxing non-obstructive dilated renal system in five babies. Renal surgery was performed in nine infants. The conclusions drawn fr om this study were that antenatal detection of renal disease is fairly accurate, even in an extremely busy hospital and certain types of mal formations reported in other studies were not observed, despite a larg e cohort.