4 day old baby: developing jaundice
Jaundice is common in newborns because the excess red blood cells that the baby required in utero have to be broken down and eliminated. A yellow pigment called bilirubin is produced and needs to be processed by the liver before it can be excreted. When the bilirubin levels are high, the pigment is deposited in the skin and the whites of the eyes, which then appear yellow.
The jaundice usually peaks at day four and disappears without treatment within 10 days. However, if levels become very high there is a risk that the pigment will be deposited in the brain causing permanent damage. To prevent this , heel prick samples will be taken to monitor bilirubin levels in your baby's blood. If they reach a certain threshold UV light or phototherapy will be given for a few hours every day.
The UV light breaks down the bilirubin in the skin, which can then be excreted in the urine without needing to be processed by the liver.