Transient urinary ascites after vesicocentesis observed in a fetus with megacystis caused by posterior urethral valve

Background: Fetal urinary ascites is a condition that is rarely encountered. A review of previous reports suggests that the clinical course of the affected fetuses is highly variable. Methods: In this report, we describe a case in which urinary ascites was observed after vesicocentesis in a fetus with megacystis caused by posterior urethral valve. Results: The urinary ascites was transient, and the fetal outcome was good after a successful vesicoamniotic shunting operation. Conclusions: In utero bladder rupture or injury and the subsequent appearance of urinary ascites may be well tolerated by the fetus. Further, spontaneous resolution can be expected during fetal life; therefore, it appears to be preferable to opt for conservative management in fetuses with urinary ascites. Urinary ascites, particularly after vesicocentesis, should be observed with extreme caution.