Evaluation of Sequential Urine Analysis when Selecting Candidates for Vesicoamniotic Shunting in Lower Urinary Tract Obstruction

Objective: The objective of our study was to assess the utility of sequential fetal urine analysis in severe lower urinary tract obstruction (LUTO) when selecting cases suitable for vesicoamniotic shunting. Material and Methods: This was a retrospective cohort study of cases of severe LUTO treated in our fetal medicine center from 1994 to 2013. Two fetal bladder samples were taken 24-48 h apart to assess renal function. A vesicoamniotic shunt was inserted in case of improvement in urinary biochemistry between the 2 samples. We assessed perinatal morbidity and mortality and renal function at 5 years. Results: Among a total of 26 LUTO cases with sequential urine analysis, 5 showed normal urinary biochemistry, 13 were abnormal, and 8 improved between the 2 samples. These 8 cases underwent vesicoamniotic shunt placement, leading to the birth of 6/8 (75%) live infants, 5/6 (83%) of whom had normal renal function at 5 years. The 5 cases with normal biochemistry occasioned 2 neonatal deaths and 3 children with normal renal function at 5 years. Elective termination of pregnancy was requested by parents for the fetuses exhibiting abnormal biochemistry. Conclusion: An improvement in urinary biochemistry between 2 sequential fetal bladder punctures in severe LUTO could be an effective criterion in the selection of candidates for vesicoamniotic shunting. However, the benefit of a shunt in fetuses with normal amniotic fluid remains to be evaluated in clinical trials.