Isolated fetal ascites is a rare condition and its natural history needs further research. We describe a case of progressive fetal isolated ascites diagnosed at 22 weeks of gestation associated with hyperechogenic bowel in a primiparous woman. Genetic abnormalities, infection and metabolic causes were excluded. An elective C-section was performed at 29 weeks of gestation after no clinical improvement was obtained with paracentesis. After birth, X-ray and ultrasonography showed high-volume ascites and enlarged liver. On the 5th day of life, no meconium had passed and an abdominal X-ray was repeated: pneumoperitoneum was diagnosed.
Laparotomy identified intestinal atresia type IIIB associated with meconial peritonitis and a derivative jejunostomy was performed. There were complications caused by late-onset sepsis and necrotizing enterocolitis. Reconstruction of jejunostomy was successfully performed on day 114. At 15 months of age, the infant is in good health and has normal psychomotor development.