Normally, bilirubin passes through the liver and is excreted as bile through the intestines. Jaundice occurs when bilirubin builds up faster than a newborn's liver can break it down and pass it from the body. Reasons for this include:
- Newborns make more bilirubin than adults do since they have more turnover of red blood cells.
- A newborn baby's still-developing liver may not yet be able to remove adequate bilirubin from the blood.
- Too large an amount of bilirubin is reabsorbed from the intestines before the baby gets rid of it in the stool.