Mechanisms of hyperbilirubinemia Hyperbilirubinemia can be caused by one or more of the following processes: Increased production Decreased hepatic uptake Decreased conjugation Impaired excretion Impaired bile flow (cholestasis) Increased enterohepatic circulation Etiology of Neonatal Hyperbilirubinemia Classification There are several ways to classify and discuss causes of hyperbilirubinemia.