Why do newborn infants get jaundice?
Jaundice, a golden yellow discoloration of the skin and eyes, is very common in newborns. About 60% of healthy, full term infants have some degree of jaundice in the first week of life. (It is even more common in premature babies.) The yellow color is due to a pigment called bilirubin, a by-product of the breakdown of red blood cells. In many newborns, the bilirubin level is high enough for the pigment to accumulate in the baby's skin, causing the golden color. Usually, the yellow color starts on a baby's cheeks and face, and then spreads downward to the chest and abdomen.
Where does bilirubin come from?
Bilirubin comes from hemoglobin (the oxygen carrying protein) in old red blood cells. As red cells are broken down in the body, the hemoglobin inside gets converted by enzymes to become bilirubin. The bilirubin is then transported in the blood to the liver. The liver processes it further (called conjugation) and then sends it to the gall bladder. The gallbladder then excretes the bilirubin into the intestine, where it goes into the baby's stool and is eliminated from the body.
Why do babies have such high bilirubin levels compared to older children?
The high bilirubin is caused by several differences between newborns and older children and adults:
- Healthy babies break down about 30% of their red blood cells in the first month of life, which tends to make a lot of leftover bilirubin. Babies with bruising or birth trauma (hematomas) can break down even more red blood cells.
- Slow livers. Right after a baby is born and cries for the first time, his or her lungs have to start to work harder. A baby's liver has to do the same, and is usually a little slow getting started.
- Delayed stooling. If a baby is "slow to poop," he or she may not get rid of the bilirubin in the intestines very quickly. The bilirubin can even get re-absorbed from the gut if the baby doesn't have many stools in the first few days of life.
- Breastfeeding. For a number of reasons too complex to describe here, breast feeding can cause elevations in bilirubin. (Note: this is a mild elevation and isn't a reason to stop breast feeding.)
When is jaundice concerning?
- Jaundice that develops in the first 24 hours of life. This is one reason why we don't like to send babies home right after delivery; we want to follow their color for the first few days. "Early" jaundice suggests that there might be a different problem going on.
- Very severe jaundice. Bilirubin levels above 20 warrant treatment (see below). In small or premature babies, we might institute treatment sooner.
- Other concerning symptoms. If the baby has any other signs of illness or infection, like fever, lethargy, poor feeding, dehydration, etc., obviously those other symptoms would need to be checked out.
How is jaundice treated?
Again, jaundice to some degree is normal in all babies, and treatment is usually not needed. Bilirubin levels of 10-15 are very common in term infants 2-4 days old and don't usually require any special treatment. On most babies who are jaundiced, we can check a bilirubin level in our office. If it is reassuring, the baby can be followed outside of the hospital. There are a few things you can do at home to help keep the bilirubin level down:
- Make sure the baby is feeding well. The more stools the baby has, the better his or her bilirubin excretion will be. If you are having trouble breastfeeding, let us know and we can make some suggestions.
- Let the baby get some sunlight on his or her skin. Light in the “blue” range converts bilirubin in the skin to a form that is more easily eliminated. Also, bright natural sunlight helps you keep track of the baby’s color better than artificial light. You can take the baby outside on a warm day or put him or her in a sunlit window in the winter.
If the bilirubin level gets very high (usually above 20), we recommend putting the baby in the hospital for a few days to get intensive phototherapy (bright light treatment) and checking bilirubin levels several times a day until it comes down.
If intensive phototherapy in the hospital doesn't bring the bilirubin level down quickly enough, the baby may need a special blood transfusion in a newborn intensive care unit. Fortunately, this is very rare.