During the neonatal period, abnormal bilirubin metabolism causes elevated bilirubin levels in the blood and a condition characterized by yellowish staining of the skin, mucous membranes and sclera, which is the most common clinical problem in newborns and is clinically referred to as neonatal jaundice. The causes of high bilirubin in newborns are as follows. First, excessive red blood cell destruction The destruction of excessive red blood cells and the increase of hepatic and intestinal circulation, so that the serum free bilirubin is elevated. This bilirubin is the main factor that induces jaundice. Liver insufficiency As the liver of newborns is not fully developed, there are not enough liver enzymes to metabolize bilirubin, and the function of hepatocytes to take up and combine bilirubin is low, so that serum free bilirubin is elevated. Because the biliary tract is not yet fully developed, newborns are unable to eliminate free bilirubin in a timely manner, resulting in excessive accumulation of bilirubin in the body, which can lead to jaundice. Delayed fetal excretion Increased hepatic and intestinal circulation. Defecation is the main way to excrete bilirubin from the body. If the newborn does not have enough intake, the defecation of fetal stool is delayed or the fetal stool is sticky, so the bilirubin will be obstructed in excretion and bilirubin will accumulate in the body and the hepatic and intestinal circulation will increase. This leads to the development of jaundice. Many newborns develop jaundice soon after birth, parents should observe carefully, if the jaundice persists or recurring, it means that the baby has pathological jaundice, at this time should be promptly sent to the doctor, do not delay.