What causes jaundice in newborn babies?

People often simply think of jaundice as yellowing of the skin, but this is only half right. Yellowing of the skin is only a superficial phenomenon. Normal human blood contains a certain amount of a pigment called bilirubin. If the bilirubin in the blood increases due to physiological and pathological reasons, the skin and whites of the eyes will turn yellow.

What are the reasons that may cause the increase of bilirubin in the body?

First, too many red blood cells are destroyed too quickly. About 80% of the bilirubin in the body is formed by the destruction of aging red blood cells. If too many red blood cells are destroyed too quickly, bilirubin will surge, causing jaundice. Hemolytic jaundice caused by incompatibility of the mother and child's blood types belongs to this category. Newborns will develop jaundice within 24 hours after birth, and it progresses quickly, with the skin showing a golden yellow color. When the bilirubin in the blood exceeds 20 mg%, bilirubin may enter the brain cells, interfere with the normal activities and functions of the brain cells, cause kernicterus, and threaten the life of the newborn. Although there are better treatments for severe jaundice at present, in order to achieve ideal therapeutic effects, timely rescue must be carried out before kernicterus occurs. When observing the degree of jaundice, parents should pay attention to choosing a place with sufficient natural light and repeatedly check whether it has worsened. Newborns with rapidly progressing jaundice should seek medical attention in time.

Second, there is a disorder in the uptake, binding and excretion of bilirubin by liver cells. Due to inflammation of liver cells or lack of an enzyme in liver cells, or low activity of this enzyme, bilirubin cannot be excreted well, such as neonatal hepatitis or sepsis. Physiological jaundice occurs in newborns within one week of birth because of low liver enzyme activity. Some babies will also develop this type of jaundice after eating breast milk, because breast milk contains a progesterone substance with a fat component. After the baby breastfeeds, this fat component is quickly broken down by lipase, releasing free fatty acids, which can increase the absorption of bilirubin by the small intestine and cause jaundice, but the baby is healthy. The above situations are all called hepatocellular jaundice.

Third, due to bile duct obstruction, bilirubin cannot be excreted into the small intestine, causing bile to accumulate in liver cells or bile ducts, causing jaundice. We call it obstructive jaundice, such as neonatal biliary atresia, thick bile, etc.