Many babies, even those who are not born prematurely, will have jaundice for at least a few days or weeks after birth. About 80% of premature babies have jaundice during the first few days of life.
Bilirubin is a naturally occurring substance produced by the breakdown of red blood cells. Shortly after birth, the baby’s liver develops the ability to process and get rid of bilirubin, but until this happens, the baby will appear slightly yellow. In addition, a preemie’s red blood cells break down more easily than those of more mature babies. In the case of premature babies, the liver may take longer to begin getting rid of the bilirubin than for full-term newborn babies.
Although very high levels of bilirubin can cause serious complications, jaundice is usually easily managed. If the baby’s bilirubin level is increased excessively, phototherapy, a special kind of light therapy, can do the trick by breaking down the bilirubin into a substance that the kidney can excrete more easily until the liver can fully take over. Bililights, which can be white, blue, or green, are simply shone on the baby’s skin. The idea of phototherapy was hit upon when, decades ago, British nurses noticed that babies near windows were less jaundiced than the other babies in the nursery.