An umbilical hernia is an outward bulging (protrusion) of the abdominal lining or part of the abdominal organ(s) through the area around the belly button.

An umbilical hernia in an infant occurs when the muscle through which blood vessels pass to feed the developing fetus doesn't close completely.

Umbilical hernias are common in infants. They occur slightly more often in African Americans. Most umbilical hernias are not related to disease. However, umbilical hernias can be associated with rare conditions such as mucopolysaccharide storage diseases, Beckwith-Wiedemann syndrome, and Down syndrome.

A hernia can vary in width from less than 1 centimeter to more than 5 centimeters.

There is a soft swelling over the belly button that often bulges when the baby sits up, cries, or strains. The bulge may be flat when the infant lies on the back and is quiet.

The doctor can find the hernia during a physical exam.

Usually, no treatment is needed unless the hernia continues past age 3 or 4. In very rare cases, bowel or other tissue can bulge out and lose its blood supply (become strangulated). This is an emergency needing surgery.

Most umbilical hernias get better without treatment by the time the child is 3 - 4 years old. Those that do not close may need surgery. Umbilical hernias are usually painless.

Strangulation of bowel tissue is rare but serious, and needs immediate surgery.

Call your health care provider, or go to the emergency room if the infant has abdominal pain, or if the hernia becomes tender, swollen, or discolored -- especially if the baby also has signs of peritonitis or shock.

There is no known way to prevent an umbilical hernia. Taping or "strapping" an umbilical hernia will not make it go away.