Spontaneous resolution of fetal ascites secondary to gastrointestinal abnormality

Abstract Objectives Isolated fetal ascites carries an uncertain prognosis and broad differential diagnosis. When detected on prenatal sonography, a thorough evaluation is warranted to exclude development of hydrops and search for an underlying condition. While gastrointestinal abnormalities account for approximately 20% of cases of fetal ascites, surgical correction is commonly required postnatally. While there have been reports of isolated fetal ascites resolving in utero, spontaneous resolution of the causative gastrointestinal abnormality is unusual. Case presentation We report a case of a multiparous 33-year-old found to have moderate fetal ascites and a complex fetal abdominal mass near the small bowel detected by ultrasound at 32 weeks with spontaneous resolution of both ascites and mass by 37 weeks. Following the delivery of a normal neonate, we suspect the mass and ascites to have been produced by a small bowel rupture resulting in meconium peritonitis. Conclusions When fetal ascites with late gestational onset has spontaneous resolution in utero and hydrops never develops, there is generally a favorable prognosis and normal neonatal outcome.