What causes breast milk jaundice?

In our lives, many people do not know what breast milk jaundice is. It refers to jaundice in breastfed babies 4 to 7 days after birth, reaching a peak at 2 to 4 weeks (serum bilirubin may exceed 256.6 to 342.0 μmol/L). The babies are generally in good condition with no signs of hemolysis or anemia.

Jaundice usually lasts for 3 to 4 weeks, gradually disappears in the second month, and in some cases may last up to 10 weeks. If breastfeeding is stopped for 3 to 4 days during jaundice, the jaundice will be significantly relieved, and the bilirubin will drop by ≥ 50%. If breastfeeding is continued, jaundice may not reappear, and even if it does, it will not reach the original degree.

Under normal circumstances, if hyperbilirubinemia occurs after birth and breastfeeding without other reasons, the bilirubin level can often reach 256.5-342μmol/L (15-20mg/dl), with indirect bilirubin elevated. The newborn is generally in good condition, feeds well, and grows and develops normally. Jaundice can last for 3 weeks to 3 months.

Breast milk jaundice may be caused by the lack of an enzyme in breast milk that promotes bilirubin metabolism, which causes the bilirubin in the child's intestines to be unable to be excreted normally. Due to the existence of enterohepatic circulation in children, bilirubin is reabsorbed back into the blood. For breast milk jaundice, bifidobacteria can be applied to children to improve normal intestinal flora, promote intestinal peristalsis, and accelerate the excretion of bilirubin, which has a good effect on the treatment of breast milk jaundice. Breast milk jaundice can gradually disappear as the child is able to produce enzymes that promote bilirubin metabolism, and generally disappears completely about three months after birth.

Generally, breast milk jaundice is divided into early-onset and late-onset according to the time of occurrence. The former occurs at a similar time to physiological jaundice, and is believed to be mainly related to improper breastfeeding and insufficient intake; late-onset is mostly believed to be related to increased enterohepatic circulation of neonatal bilirubin metabolism, which usually occurs 1 to 2 weeks after birth and can last up to 8 to 12 weeks.

It is generally believed that the content of glucuronidase in the small intestine of newborns is high (confirmed by testing) and has high activity. This enzyme, which is mainly derived from breast milk, can catalyze the conversion of conjugated bilirubin into unconjugated bilirubin. This process takes place in the small intestine of newborns. In addition, the intestinal peristalsis of children is relatively slow, so a large amount of bilirubin that should be excreted is dissociated into unconjugated bilirubin by this enzyme, and absorption increases, that is, breast milk jaundice occurs.