What causes high jaundice in newborns after birth?

Elevated jaundice in newborns is generally caused by factors such as intrauterine hypoxia, maternal-infant blood type incompatibility, or breastfeeding.

1. Intrauterine Hypoxia

If the intrauterine environment is poor during delivery—for example, due to intrauterine infection or endometrial polyps—the fetus may experience hypoxia. This can lead to an increased number of red blood cells and excessive bilirubin production, which commonly results in high jaundice levels after birth.

2. Maternal-Infant Blood Type Incompatibility

If the newborn's blood type is incompatible with the mother's, it can easily cause destruction of the newborn's red blood cells, resulting in a large accumulation of bilirubin. Over time, continued elevation of bilirubin levels can lead to significantly high jaundice.

3. Breastfeeding

After birth, if the infant is breastfed, the breast milk typically contains relatively high levels of glucuronidase activity. This enzyme promotes reabsorption of bilirubin in the newborn's intestines, leading to elevated blood bilirubin levels and consequently higher jaundice.