P316: Postmortem findings in fetuses with severe lower urinary tract obstruction

Abstract

To examine the underlying pathology in fetuses with sonographic evidence of severe urethral obstruction. Detailed postmortem examination was carried out after termination of pregnancy in 10 fetuses presenting before 22 weeks of gestation with ultrasound evidence of severe low urinary tract obstruction. There was megacystis in all cases, anhydramnios/oligohydramnios in nine cases, pelvicalyceal dilatation in 6 cases and hyperechogenic kidneys in 9 cases. Gender was male in all cases. Postmortem examination, including histological investigation of the urethra and kidneys, demonstrated renal dysplasia in all cases. Similarly, there was megacystis in all fetuses but the bladder wall was thick in nine and thin in one case. Examination of the urethra demonstrated atresia or severe stenosis in eight cases, posterior urethral valves in one case and an apparently normal urethra in one. The vast majority of fetuses presenting with sonographic features of severe low obstructive uropathy, the underlying cause is urethral atresia or severe stenosis. When these present in the first or early second trimester of pregnancy in a male fetus the prognosis is poor.