Incidence in full-term newborns 30-60% and in nearly all premature infants.
Average full term newborn has a bilirubin of 5 to 6 mg/dL.
In neonates serum bilirubin peaks on 3rd or 4th day of life and then decline over the next 3-4 days.
Bilirubin higher than 17 mg/dL no longer considered physiologic jaundice.
Most cases due to immaturity of hepatic enzyme system that converts uncongugated insoluble bilirubin to soluble conjugated bilirubin.
Neonatal hyperbilrubinemia can be associated with severe illnesses such as hemolytic disease, metabolic and endocrine disorders, anatomic abnormalities of the liver and infections.
Risk factors include fetal-maternal blood group incompatibility, prematurity, bruising, cephalohematomas, trauma from an instrument delivery, delayed meconium passage and a history of an affected sibling.
In nonphysiologic jaundice bilirubin increases at a rate of >0.5 mg/dL or 5 mg/dL and exceed 15 mg/dL in a term infant and 10 mg/dL in a preterm infant.
Nonphysiologic jaundice associated with hemolytic disease of the newborn.
Phototherapy is the primary treatment.
Exchange transfusion may be necessary if phototherapy is ineffective.