Jaundice is a term used to describe the yellowish discoloration that develops in the skin due to a buildup of bilirubin. In the newborn period, it's most often a temporary condition that happens when a newborn's liver is still immature and not yet able to help the body get rid of bilirubin. Bilirubin is a substance that is found in the red blood cells. It can build up after birth as a result of the normal breakdown of red blood cells. If bilirubin levels get too high, they can be dangerous to your baby's developing brain and nervous system. That is why it's important to check babies who have signs of jaundice to make sure the bilirubin level doesn't become unsafe. An immature liver is normal at this stage of your baby's growth. It will quickly start to remove bilirubin from the body. Almost half of all newborns show some signs of jaundice, such as yellow skin or eyes.