Umbilical herniation occurs because there is not enough room in the abdomen for the developing midgut. The lack of space in the abdomen is due to the developing liver and kidneys, which are relatively large at this stage in development.

Sometimes, the herniated gut does not return to the abdominal cavity, and an omphalocoele results, requiring surgical intervention. Similarly, the umbilical ring may remain larger than normal, resulting in an umbilical hernia seen soon after birth. These umbilical hernias are usually small and resolve themselves in the months following birth.