Ultrasound appearance of fetal greater omentum

Fetal ascites results in the ultrasonographic demonstration of normal structures within the fetal abdomen that are otherwise not seen. One such structure is a membrane that, when surrounded by intraperitoneal fluid, may simulate a loculated area of fluid or a fluid-filled viscus. On the basis of its configuration and site of insertion observed during real-time and static ultrasonography, we believe that this membrane is the greater omentum. Recognition of the typical appearance of greater omentum floating in fetal ascites will prevent the erroneous diagnosis of an abnormal intra-abdominal fluid collection.