Fetal urinary electrolytes in bladder outlet obstruction.

Ultrasound findings and urinary electrolytes in the fetus were correlated with fetal outcome and postmortem findings in 8 cases of fetal bladder outlet obstructions. One of the two fetuses, suggesting normal renal function according to urinary electrolytes, displayed renal dysplasia at birth. Six fetuses were predicted to have poor renal function, 5 of these were found to have renal dysplasia at autopsy. The interpretation of fetal urinary electrolytes as a prognostic indication for the presence or absence of renal dysplasia needs to be clarified.