Intra-uterine cystography for evaluation of prenatal obstructive uropathy.

To evaluate the risk for kidney damage in a male fetus with obstructive uropathy, a percutaneous bladder puncture was performed at 26 weeks gestational age and contrast was injected into the fetal bladder. A clear picture was obtained of the bladder with marked widening of the prostatic urethra and posterior urethral valves, and massive bilateral vesicoureteral reflux could be demonstrated. By adding cysto-urethrography to a diagnostic puncture of the fetal bladder it could be proved that the dilatation of the upper urinary tracts was caused by high-pressure vesico-ureteral reflux incurring progressive damage to the renal parenchyma.