Sequential urinalysis improves evaluation of fetal renal function in obstructive uropathy

OBJECTIVES: The purpose of our study was to determine whether sequential vesicocenteses improve the evaluation of renal damage, compared with single urine sampling in obstructive uropathy. STUDY DESIGN: A total of 29 fetuses with complete obstructive uropathy underwent a minimum of three sequential complete vesicocenteses at 48- to 72-hour intervals. First and last urine values were analyzed for multiple parameters. The ability of first versus last urine values to detect the presence of renal damage was compared according to postnatal or fetal autopsy information. RESULTS: Fetuses with minimal renal damage had patterns of decreasing hypertonicity and last urine values below cutoff thresholds indicative of favorable prognosis. Fetuses with significant renal damage had higher initial values and patterns of increasing hypertonicity. For five of six parameters, last urine samples were more predictive of renal damage than first urine samples. CONCLUSION: Last urine values together with pattern-of-change trend analysis after serial vesicocenteses improve diagnostic precision in fetuses with complete obstructive uropathy.