This bulge in the navel is caused by protrusion of the infant's small intestines through a hole or weakness in the abdominal wall at the point where the umbilical cord was attached during pregnancy. The bulge is usually smaller than one inch; longer protrusions are unusual. Small umbilical hernias may bulge out only when the baby is straining, crying or coughing. Most hernias are soft to the touch and can be pushed back into place with gentle pressure.

Umbilical hernias are especially common in low-birth weight babies and black babies. They occur more often in girls than boys. Umbilical hernias and inguinal hernias are the most common hernias in infants. With rare exceptions, umbilical hernias are neither painful nor dangerous. In less than one percent of umbilical hernias, however, the hernia becomes entrapped (or incarcerated), potentially cutting off the blood supply to the herniated intestine. An interrupted blood supply may make the intestine decay and become infected, a condition known as gangrene. The intestine can also become perforated by the constriction. An entrapped umbilical hernia is a medical emergency.

WHAT CAUSES AN UMBILICAL HERNIA?
The umbilical cord connects the fetus to the placenta, passing through an opening in the abdominal wall of the fetus and providing essential nutrients to the fetus. After birth, the umbilical cord is cut and tied to form the navel, and the opening in the muscles of the abdominal wall closes. In children with umbilical hernias, the muscles in the abdominal wall do not close completely, leaving either an opening or a weakened area. The intestines can then push through, causing the hernia.

WHEN SHOULD I SUSPECT THAT MY CHILD HAS AN UMBILICAL HERNIA?
Any bulge protruding from the infant's navel may indicate an umbilical hernia. If the hernia is soft and can be pushed back into the abdominal cavity, there is no reason for worry. If the bulge is hard to the touch and cannot be pushed into place or if the herniated area is tender, the segment of intestine may be entrapped.

IS MEDICAL ATTENTION NECESSARY?
Only if the hernia is entrapped, which is a very rare occurrence. Umbilical hernias are benign. The pediatrician should, however, check for any changes in the hernia and determine whether it is receding properly during regularly scheduled medical checkups.

Most umbilical hernias that appear before the infant is six months old will disappear by the age of one. At or soon after that age, the muscles of the abdominal wall are usually closed. Larger hernias may take as long as five or six years to recede.

WHAT TREATMENTS ARE AVAILABLE?
In most cases, no treatment is needed. Surgery, which takes under an hour and rarely requires a hospital stay, may be recommended for hernias that enlarge or persist past the age of five or six. Immediate surgery is needed for entrapped umbilical hernias.

CARING FOR A CHILD WITH AN UMBILICAL HERNIA
Do not bind the child's navel in an attempt to push the protrusion back in. This outmoded practice does not help and may possibly be harmful.

Excerpt from THE DISNEY ENCYCLOPEDIA OF BABY & CHILD CARE, © 1995 DSH Communications, Inc. This material is based on current medical research and, to the best of the editors' knowledge and understanding, is accurate and valid. However the reader should not use information contained in this material to alter a medically prescribed regimen or as a form of self-treatment, without seeking the advice of a licensed physician.