The pathophysiology of umbilical hernia involves the weakness of abdominal fascia or failure to fully form the fascia which may lead to an umbilical hernia in the newborn. During the fifth to tenth weeks of gestation, the intestinal tract undergoes rapid growth with protrusion of the abdominal content outside the abdominal cavity. This is followed by a gradual re-entry of the abdominal cavity and then the narrowing of the umbilical ring which completes the process of abdominal wall formation.

The pathophysiology of umbilical hernia is as follows:^[1][2]

• During fetal development, the abdominal wall is formed by four separate embryologic folds:
  • Cephalic
  • Caudal
  • Right and left lateral
• Each fold is composed of somatic and splanchnic layers.
  • The folds develop towards the anterior center portion of the coelomic cavity (derived from mesoderm in humans) and ultimately join to form a large umbilical ring that surrounds the following structures:
    • Two umbilical arteries
    • Umbilical vein
    • Yolk sac (omphalomesenteric duct)
  • These structures are enclosed by the outer layer of amnion.

• During the time between fifth and tenth weeks of gestation, the intestinal tract undergoes rapid growth with protrusion of the abdominal content outside the abdominal cavity.
• This is followed by a gradual re-entry of the abdominal cavity and then the ultimate narrowing of the umbilical ring which completes the process of abdominal wall formation as fetal development concludes.
• Weak fascia or failure to fully form the fascia may predispose the newborn to an umbilical hernia.

• Patients with the following pre-existing diseases:
  • Mucopolysaccharide storage diseases
  • Beckwith-Wiedemann syndrome
  • Down syndrome