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.
There are a number of causes that could be responsible for a bowel obstruction, both mechanical and non-mechanical. Paralytic ileus refers to a non-mechanical obstruction where the rhythmic muscle contractions of the intestine, known as peristalsis, stops.