Excess bilirubin (hyperbilirubinemia) is the main cause of jaundice. Bilirubin, which is responsible for the yellow color of jaundice, is a normal part of the pigment released from the breakdown of "used" red blood cells.
Newborns produce more bilirubin than adults do because of greater production and faster breakdown of red blood cells in the first few days of life. Normally, the liver filters bilirubin from the bloodstream and releases it into the intestinal tract. A newborn's immature liver often can't remove bilirubin quickly enough, causing an excess of bilirubin. Jaundice due to these normal newborn conditions is called physiologic jaundice, and it typically appears on the second or third day of life.
An underlying disorder may cause infant jaundice. In these cases, jaundice often appears much earlier or much later than does the more common form of infant jaundice. Diseases or conditions that can cause jaundice include:
- Internal bleeding (hemorrhage)
- An infection in your baby's blood (sepsis)
- Other viral or bacterial infections
- An incompatibility between the mother's blood and the baby's blood
- A liver malfunction
- Biliary atresia, a condition in which the baby’s bile ducts are blocked or scarred
- An enzyme deficiency
- An abnormality of your baby's red blood cells that causes them to break down rapidly
Mild infant jaundice often disappears on its own within two or three weeks. For moderate or severe jaundice, your baby may need to stay longer in the newborn nursery or be readmitted to the hospital.
Treatments to lower the level of bilirubin in your baby's blood may include:
- Enhanced nutrition. To prevent weight loss, your doctor may recommend more-frequent feeding or supplementation to ensure that your baby receives adequate nutrition.
- Light therapy (phototherapy). Your baby may be placed under a special lamp that emits light in the blue-green spectrum. The light changes the shape and structure of bilirubin molecules in such a way that they can be excreted in both the urine and stool. During treatment, your baby will wear only a diaper and protective eye patches. Light therapy may be supplemented with the use of a light-emitting pad or mattress.
- Intravenous immunoglobulin (IVIg). Jaundice may be related to blood type differences between mother and baby. This condition results in the baby carrying antibodies from the mother that contribute to the rapid breakdown of the baby's red blood cells. Intravenous transfusion of an immunoglobulin — a blood protein that can reduce levels of antibodies — may decrease jaundice and lessen the need for an exchange transfusion, although results are not conclusive.
- Exchange transfusion. Rarely, when severe jaundice doesn't respond to other treatments, a baby may need an exchange transfusion of blood. This involves repeatedly withdrawing small amounts of blood and replacing it with donor blood, thereby diluting the bilirubin and maternal antibodies — a procedure that's performed in a newborn intensive care unit.