ATLANTA, Georgia (CNN) -- Jaundice is a common condition that affects six out of 10 newborns, according to the March of Dimes. CNN learned more about infant jaundice from Dr. Anne Hansen, a neonatologist at Children's Hospital in Boston, Massachusetts.
Light of a specific wavelength can turn bilirubin into a chemical easier for babies to excrete.
CNN: What is jaundice?
Hansen: Jaundice refers literally to the yellow discoloration of the skin and eyes of babies who have high bilirubin levels in their blood. Bilirubin is a yellow pigmented chemical that is released from red blood cells.
CNN: What causes it?
Hansen: Newborns have a higher red blood cell mass than older babies. So as those red blood cells break down, they release the bilirubin and there is more bilirubin in the blood. Newborns also have an immature liver, and the bilirubin is processed in a complex manner, but it requires the liver. So the combination of the increased red blood cell mass and the immaturity of the liver means that more is being produced and less is being excreted.
CNN: What are the symptoms?
Hansen: If a baby has mild jaundice, they will have no symptoms because they are not sick. They will just appear slightly yellow. Classically, the yellow discoloration starts at the top of the baby's head and moves down from there. The earlier signs of jaundice are seen on the scalp, the face and in the whites of the eyes. If the legs, soles of the feet and palms of hands are jaundiced, that probably means the baby has a high bilirubin level. Health Minute: Watch more on infant jaundice »
CNN: When should you call a doctor?
Hansen: If babies have very high bilirubin levels and are developing a brain injury, they will be lethargic, un-arousable and very sleepy. They may be agitated. They may have arching movements of their back. They may have a high-pitched cry or even seizures.
CNN: What is the relationship between breastfeeding and jaundice?
Hansen: Breastfeeding jaundice is the result of the fact that mothers who exclusively breastfeed their babies do typically have a little less volume of milk to offer in the first few days as their volume of milk supply is building. These babies are slightly dehydrated and they take in slightly fewer calories than a formula-fed baby.
CNN: How does that differ from another condition called breast-milk jaundice?
Hansen: Breast-milk jaundice is a bit more complicated. We know that there is some component in breast milk that does cause blood bilirubin levels to rise above formula-fed babies.
CNN: How do you treat these types of jaundice?
Hansen: The treatment for breastfeeding jaundice is to increase the frequency of the breastfeeding. Feed babies every two to three hours. It treats dehydration and increases caloric supply. The treatment for breast-milk jaundice is that mothers may be asked to pump and store their breast milk for two or three days and to give their babies formula in the meantime that will help the bilirubin to drop.
CNN: Many babies are treated with phototherapy. How does it work?
Hansen: The way that works is it takes advantage of the fact that the bilirubin makes its way out of the blood and into the baby's skin. When the skin is exposed to a particular wavelength of light that is in the blue range of the spectrum, it transforms the bilirubin into another chemical that is harmless and easier for the baby to excrete. The phototherapy tends to be only needed for a couple of days and babies usually go home without any long-term medical concerns. E-mail to a friend
Judy Fortin is a correspondent with CNN Medical News. Linda Ciampa of Accent Health contributed to this report.