Which form of bilirubinemia is predominantly seen in breastfeeding jaundice?

Breastfeeding jaundice is primarily associated with an increase in unconjugated bilirubin levels in newborns. This condition typically arises due to inadequate milk intake, which can lead to dehydration and increased reabsorption of bilirubin from the intestines. When a newborn does not receive sufficient breast milk, the liver may not effectively process bilirubin, resulting in elevated levels of unconjugated (or indirect) bilirubin in the bloodstream.

Unconjugated bilirubin is the form that is not water-soluble and is produced from the breakdown of heme in red blood cells. In infants, the liver is still maturing, and various factors, including dehydration and insufficient feeding, can exacerbate the buildup of this unconjugated form.

In contrast, direct hyperbilirubinemia and conjugated hyperbilirubinemia refer to bilirubin that has been processed and made water-soluble in the liver. These forms typically indicate different underlying conditions, such as hepatic disorders or biliary obstruction. Therefore, in the context of breastfeeding jaundice, the predominant increase is in unconjugated bilirubin due to factors related to inadequate breastfeeding.