Hyperbilirubinemia is the medical term for jaundice in a newborn caused by an excessive amount of bilirubin in the blood. Bilirubin is the substance formed when red blood cells break down, and newborns are not yet able to eliminate it from the body. When this substance builds up in the blood and other fluids of the body it leads to jaundice, or a yellowing of the skin and tissue. Jaundice may appear at birth or any time afterward, depending on the underlying cause of the hyperbilirubinemia.
When a baby is inside the womb, the placenta excretes bilirubin. When the baby is born, however, the liver begins to take over this function. Hyperbilirubinemia occurs due to the baby's limited ability to get rid of the substance during the first few days after birth. Yellowing of the skin is a common occurrence amongst newborns due to this problem, which is known as physiological jaundice.
Other common causes of hyperbilirubinemia include hemolytic disease and inadequate liver function. Hemolytic disease, also known as Rh disease, is a condition in which too many red blood cells are present in the body. This leads to jaundice when the excessive red blood cells produce too much bilirubin. The baby cannot excrete the bilirubin quickly enough, so it begins to build up in the blood, causing the characteristic yellowing of the skin.
Both full-term newborns and premature newborns can be affected by hyperbilirubinemia. It is more common in newborns that were born prematurely, most likely because the organs have not been fully developed and are not completely functioning at birth. Babies with diabetic mothers or mothers with Rh disease are also more likely to develop the condition.
In most cases, hyperbilirubinemia is not a life threatening condition and no medical treatment is required. The infant will eventually begin to excrete the excess bilirubin in the blood and return to normal. If the intensity of the yellow skin pigment increases or the baby's behavior changes, however, this could be an indication of harmful levels of bilirubin in the blood. It's always best to consult a physician if jaundice is observed in an infant to make sure that the bilirubin levels are not high enough to cause damage. If the levels become too high and treatment is not administered, the condition can cause brain damage, behavior problems, hearing loss and mental retardation.
The most common treatment for hyperbilirubinemia is phototherapy, which consists of exposing the infant to bright, fluorescent light. The light transforms the bilirubin in the blood into a substance that the body can more easily eliminate. Phototherapy is typically administered in a hospital, but can also be used to treat the child at home in mild cases. If the jaundice is caused by an underlying condition, this problem will need to be treated. In very rare and severe cases, a blood transfusion may be necessary to treat the hyperbilirubinemia.