Bilirubin is a brownish, yellowish substance produced by the breakdown of red blood cells. During pregnancy, the placenta excretes bilirubin. A baby’s liver must take over this function once the baby is born. The coloring of the bilirubin causes the baby’s eyes and skin to appear yellow.
There are several reasons a newborn can develop jaundice, including:
- Physiologic jaundice is a normal response to a baby’s limited ability to excrete bilirubin in the first days of life.
- Breastfeeding jaundice occurs in some babies in the first week due to low milk intake or dehydration.
- Breast-milk jaundice occurs in some babies in the second week of life or later for unknown reasons. It may be related to a substance in the breast milk that makes it easier for the intestine to reabsorb the bilirubin or due to the immature liver processing of bilirubin.
- Jaundice from hemolysis is a condition that results from excess breakdown of red blood cells due to hemolytic disease of the newborn (HDN), polycythemia, or hemorrhage.
- Inadequate liver function due to infection or other factors.
In most cases of breastfeeding jaundice and breast-milk jaundice, doctors recommend that the mother continue breastfeeding.
In a small number of cases, jaundice in a newborn can be a sign of:
- Cholestasis, a rare condition caused by a problem with the production or flow of bile
- Biliary atresia, a rare condition in which the duct that carries bile from the liver to the small intestine is blocked or damaged