This midgut herniation (sometimes called physiological omphalocele) is caused by a relatively rapid growth of the midgut, accompanied by a 270° anticlockwise midgut rotation in the abdominal cavity. Return into the body is caused by rapid growth of the body or decrease in the length of the mesentery.

Why does normal midgut herniation occur?

It occurs as a result of the bowel (particularly ileum) growing faster than the abdominal cavity during the early gestational period. In the physiological situation, the intestine elongates and moves outside of the embryonic abdomen herniating into the base of the umbilical cord.

How common is midgut herniation?

A cross-sectional study of 61 embryos-fetuses from 7 to 12 weeks of gestation was performed to observe the physiologic midgut hernia. This herniation was detected in 64% of the cases at 8 weeks, in 100% during weeks 9 and 10, and in 25% at 11 weeks' gestation.