Nonimmune fetal ascites: a series of 79 cases.

Objective: The purpose of this study was to analyze the precision of ultrasonography in defining the cause and prognosis in fetal ascites.

Study Design: We conducted a retrospective study of 79 cases of fetal ascites.

Results: The mortality rate was 57% overall and ranged from 100% (7/7 cases) for metabolic storage disease to 0% (0/3 cases) in chylous ascites. Ascites before 24 weeks of gestation or combined with fetal hydrops indicates poor prognosis (respectively, 78.6% vs 45% mortality rate after 24 weeks; P<.01; and 77% vs 50.8% without hydrops; P<.02). Ascites was organic in 45 cases, infectious in 13 cases, idiopathic in 12 cases, and genetic in 9 cases. The cause was defined ultrasonographically in 28 of the 45 organic ascites and in 8 of the 25 isolated ascites. Urinary cause was the most frequent and the most successfully specified cause (14/15 cases).

Conclusion: Routine ultrasonography detects fetal ascites, but the cause is extremely variable and difficult to specify. When associated with fetal hydrops, the prognosis is poor.