Omphalocele is a disorder characterized by a midline defect involving the abdominal wall muscles and resulting in herniation of intra-abdominal structures into the base of the umbilical cord. The hernia is covered by peritoneum, amnios, and Wharton's jelly. In cases of omphalocele, the cord inserts on the sac and the size of the defect and hernia vary with the amount and type of herniated structures. Omphaloceles are associated with other anomalies in more than 70% of the cases. Cardiac anomalies occur in 30-50% of the cases and are often complex (ASD, VSD, tetralogy of Fallot, pulmonary stenosis, aortic coarctation, transposition of the great arteries). In some cases, omphalocele is part of a polymalformative syndrome, such as Beckwith-Wiedemann Syndrome, pentalogy of Cantrell, short umbilical cord syndrome, amniotic band syndrome, or cloacal exstrophy. In cases with associated cardiac defects the mortality rate approaches 80%. The incidence of omphalocele is 2.5/10000 births.

Chromosomal anomalies are also commonly present (10-40%) and include trisomy 13, 18, or 21, Turner Syndrome, and triploidy (23, 27). The prognosis for a child with omphalocele is related to the presence of associated chromosomal and structural anomalies.