Causes Most cases involve unconjugated hyperbilirubinemia. Some of the most common causes of neonatal jaundice include Physiologic hyperbilirubinemia Breastfeeding jaundice Breast milk jaundice Pathologic hyperbilirubinemia due to hemolytic disease Liver dysfunction (eg, caused by parenteral alimentation causing cholestasis, neonatal sepsis, neonatal hepatitis) may cause a conjugated or mixed hyperbilirubinemia.