Outcome of posterior urethral valves: To what extent is it improved by prenatal diagnosis?

Purpose: To assess the impact of prenatal diagnosis and evaluation on the o utcome of posterior urethral valves we studied all cases of valves detected prenatally, including cases of pregnancy termination due to posterior uret hral valves. Materials and Methods: Between 1989 and 1996, 30 neonates with prenatally d etected posterior urethral valves were treated at our hospital. The prenata l parameters analyzed were age of gestation at diagnosis, ultrasonographic appearance of renal parenchyma and amniotic fluid volume. Fetal urine was a nalyzed in 9 cases. We reviewed the outcome of 10 neonates treated for post erior urethral valves which were not diagnosed prenatally during the same p eriod. Results: Of the 30 neonatal survivors 6 (20%) had renal failure, including end stage renal disease in 2, after a mean followup of 4 years. Renal failu re developed in 2 of 5 eases detected before 24 weeks of gestation, in I of 6 with oligohydramnios and in 2 of 5 with abnormal parenchymal renal ultra sound. Normal parenchymal ultrasound and amniotic volume could not predict for good outcome. Renal failure developed in 2 of 7 cases predicted by feta l urinalysis as good prognosis and in 1 of 2 cases predicted as poor progno sis. Pregnancy was terminated for posterior urethral valves in 5 cases base d on prenatal criteria of severe renal impairment. Considering these cases as poor outcome, the rate of poor prognosis increased from 20 to 31%. Among the 10 neonates without a prenatal diagnosis of posterior urethral valves renal failure developed in 2 (20%), including end stage renal disease in 1. Conclusions: When negative parameters were absent and/or fetal urine predic ted good outcome there were no cases of end stage renal disease in early in fancy, which was a significant help in parent counseling. The predictive va lue of the currently available prenatal parameters needs to be updated with larger series specifically dealing with posterior urethral valves. Accordi ng to the current data, the outcome of posterior urethral valves is not yet significantly improved by prenatal diagnosis.