Jaundice in newborn babies

Jaundice is caused by a build‑up of bilirubin, a yellow substance made when red blood cells break down. Newborns have extra red blood cells and immature livers, so bilirubin can build up and turn their skin yellow.

Jaundice is common and usually improves with good feeding, which helps remove bilirubin through poo and wee.

Babies are more at risk if they’re premature (before 36 weeks), have an infection, rhesus disease, or liver conditions such as biliary atresia. Some cases are linked to medical conditions and need treatment.