High bilirubin in newborns is what is known as jaundice. In general, the normal blood bilirubin concentration should be between 5 and 7 mg/dl. If it is greater than this, jaundice visible to the naked eye can occur. In general, if the jaundice is not very high and if there are no other clinical abnormalities, such as poor mental status and fever, the jaundice usually returns to normal. However, if the jaundice is very high, especially in preterm infants, because the blood-brain barrier is not well developed and the barrier function is weak, the bilirubin is very high at this time and can enter the central nervous system. And it causes bilirubin encephalopathy, a phenomenon often referred to as nuclear jaundice. Nuclear jaundice often leads to convulsions and coma in babies, and can cause cerebral palsy in severe cases. Therefore, newborns with significantly higher jaundice must be taken seriously and treated actively.