<unk>  can affect up to 84% of term newborns and is often a benign process that is quickly corrected once identified. It is also the most common cause for hospital readmission for neonates post birth.
The most important piece of the evaluation is distinguishing between unconjugated and conjugated hyperbilirubinemia since a conjugated (direct) hyperbilirubinemia is always pathologic and often more severe
Isoimmune hemolytic disease
G6PD deficiency
Asphyxia
Significant lethargy
Temperature instability
Sepsis
Acidosis
Prematurity
Poor PO intake
Neonatal jaundice
More common causes are listed first, followed by less common causes
Breast milk jaundice
Breast feeding jaundice
Due to substances in milk that inhibits glucuronyl transferase. It may start as early as 3rd day and reaches peak by 3rd week of life. It is unlikely to cause kernicterus
Biliary atresia
Neonatal hypoglycemia
Patient does not receive adequate oral intake which then causes reduced bowel movement/bilirubin excretion. Best diagnosed by looking for signs of dehydration and comparing weight to birth weight.