URINARY-TRACT ANOMALIES DETECTED BY PRENATAL ULTRASOUND EXAMINATION AT MAYO-CLINIC ROCHESTER

Objective: To determine the frequency of fetal urinary tract anomalies and to characterize the types of such abnormalities detected on ultra sonography and the outcome of affected patients during a 15-year perio d at our institution. Design: We retrospectively reviewed the findings on maternal prenatal ultrasound examinations and the postnatal medica l records of 56 children with urinary tract abnormalities detected by prenatal ultrasound examination at Mayo Clinic Rochester from November 1979 to June 1994. Results: Of the 56 children, 18 (32%) had severe u rinary tract anomalies in conjunction with oligohydramnios, pulmonary hypoplasia, and perinatal death (Potter's syndrome), The other 38 infa nts had various urinary tract abnormalities-most commonly, isolated hy dronephrosis and multicystic dysplasia of the kidney, Six of the 38 ch ildren had more than one renal abnormality detected prenatally, Reflux was noted in association with prenatally detected urinary tract abnor malities in 4 of 32 newborns (12%) who underwent voiding cystourethrog raphy, In fetuses with normal amniotic fluid volume, the perinatal out come was good, Children with lower urinary tract obstruction had evide nce of more severe renal dysfunction than did those with involvement a t more proximal levels, The presence or absence of urinary tract obstr uction postnatally could not be determined reliably on the basis of pr enatal ultrasound appearance. Conclusion: In this study, more than hal f of all prenatally detected urinary tract abnormalities were isolated hydronephrosis or multicystic dysplasia of the kidney, Postnatal rena l function could not be reliably predicted on the basis of prenatal ul trasound findings.