Q: What causes jaundice in most newborn babies?
A: Jaundice occurs when bilirubin levels get too high in the blood. Bilirubin is a pigment that we all have in our bodies to some degree. It is a by-product of the breakdown of red blood cells. Bilirubin is normally "processed" by the liver and excreted in the stool and urine. It is what gives the stool a brown color, and the urine a yellow color. When the level of bilirubin gets too high, it can be deposited in the skin giving a yellow tinge--or in the white portion of the eyes making them look yellow. This is jaundice.
Jaundice occurs in most normal newborns. This is referred to as "physiologic jaundice of the newborn." What happens in this condition, is that the liver in the new baby is immature. It gets overwhelmed by the load of bilirubin and is unable to process it all at once. Jaundice results, but rarely is a problem. The jaundice peaks by the third to fourth day after which the liver reaches its full functional potential. The excess bilirubin is taken care of and the jaundice resolves, leaving the pink baby that one was expecting.
If the bilirubin level gets too high, it can be harmful to the central nervous system. To avoid this from happening, the baby can be treated with phototherapy, or so-called "bili-lights." The baby is placed under flourescent lights in a special crib, wearing only protective eye patches. The lights metabolize the bilirubin through the skin and get rid of the excess. The duration of therapy is usually 2-3 days during which time the level of bilirubin can be monitored through blood tests. There is also a special fiber-optic "blanket" that bathes the neonate in flourescent lights. This can be used in the home and is very convenient and very popular. It has greatly curtailed the need to hospitalize babies with very high bilirubins.
In the rare instance, breast milk may cause prolonged jaundice in a normal baby. If this happens, the doctor will usually recommend that you withhold breast milk for a couple of days until the bilirubin level comes down. Once this occurs, you can resume breast feeding without any fear of the bilirubin rising.
There are many other causes of jaundice that can occur in newborns or young infants. These are not normal, and are usually associated with more serious conditions. As a rule, if the jaundice persists beyond the first couple of weeks of life, that baby needs a very thorough exam by his/her doctor, and specific lab tests should be performed.