Jaundice is a yellow color in the skin and eyes. It is caused by a buildup of bilirubin in the blood, which is then deposited in the tissues. Bilirubin is a breakdown product of hemoglobin, the oxygen carrying part ofthe red blood cell.

While in the uterus, the baby has blood cells which contain fetalhemoglobin. These cells are very good at getting oxygen from the blood inthe umbilical cord, but not so good at getting oxygen from the air in thelungs. Consequently, the baby immediately starts destroying the fetal blood cells and replacing them with "adult" blood cells. The resulting bilirubinis broken down in the liver to be eventually excreted in the urine and feces.

There are many causes of jaundice, some serious, some not. Fortunately, themost common form is "physiologic jaundice," meaning the liver is not quiteready to handle the extra load. This occurs in almost 50 percent of infants and usually resolves in a few days. Jaundice can also signal seriousproblems, however, including sepsis (blood infection), liver failure andabnormal destruction of red blood cells. Your physician can check to see what's causing jaundice if it occurs.

The worst complication of jaundice is kernicterus, a situation where bilirubin is deposited in the brain. This can cause brain damage or death. Fortunately, it is extremely rare, and occurs almost exclusively in preterm infants with very high levels of bilirubin.

Treatment usually involves phototherapy (ultraviolet light) and hydrationwith fluids. Rarely, women may be asked to stop breastfeeding for 24 hours. If the bilirubin gets to dangerous levels, exchange transfusion can be performed, where some of the infant's blood is removed and replaced with adult blood.