Diagnosis of fetal anterior abdominal wall defects by use of ultrasonography.

Omphalocele and gastroschisis involve protrusion of intestine through a defect in the abdominal wall. It is important to differentiate between the two because of a difference in the incidence of associated anomalies and of chromosomal abnormalities. The distinguishing characteristics are the location of umbilical cord insertion, the echogenicity of the contents of the protruding mass and, usually, the presence or absence of a sac surrounding the mass. Early detection is critical so that decisions can be made about the possibility of surgical correction and the outcome of the pregnancy. We describe an omphalocele detected by ultrasonography in the 20th week of gestation during a routine prenatal check-up.