Jaundice is a condition that makes a newborn’s skin and the white part of the eyes look yellow. It happens because there is too much bilirubin in the baby’s blood (hyperbilirubinemia). Bilirubin is a substance that is made when the body breaks down old red blood cells.

Jaundice usually is not a problem. But in rare cases, too much bilirubin in the blood can cause brain damage (kernicterus). This can lead to hearing loss, mental retardation, and behavior problems.

In healthy babies, some jaundice almost always appears by 2 to 4 days of age. It usually gets better or goes away on its own within a week or two without causing problems.

In breast-fed babies, mild jaundice sometimes lasts until 10 to 14 days after birth. In some breast-fed babies, it goes away and then comes back. Jaundice may last throughout breast-feeding. This isn't usually a problem as long as the baby gets enough milk by being fed at regular times.  WebMD