During pregnancy, the umbilical cord passes through a small opening in the baby's abdominal muscles. The opening normally closes just after birth. If the muscles don't join together completely in the midline of the abdomen, this weakness in the abdominal wall may cause an umbilical hernia at birth or later in life.
Ileus may also be caused by an infection inside the abdomen, such as appendicitis or diverticulitis. Disorders outside the intestine, such as kidney failure, an underactive thyroid gland, or abnormal levels of blood electrolytes (low potassium levels or high calcium levels, for example), may cause ileus.
Ogilvie pseudo-obstruction in a septic elderly patient. Note the massive dilatation of the colon, especially the right colon and cecum. Although ileus has numerous causes, the postoperative state is the most common setting for the development of ileus. Indeed, ileus is an expected consequence of abdominal surgery. Physiologic ileus spontaneously resolves within 2-3 days, after sigmoid motility returns to normal.