important causes of hemolysis Other extrinsic causes of RBC destruction include the autoimmune, microangiopathic, and drug-induced hemolytic anemias Birth trauma, when associated with cephalohematoma, extensive bruising, or swallowed maternal blood, can result in hyperbilirubinemia Intracranial, pulmonary, or other concealed hemorrhage can also lead to extravascular hemolysis Similarly, polycythemia, caused by delayed clamping of the cord or maternal–fetal or fetal–fetal transfusion (in multiple gestations), increases the RBC mass and causes jaundice in neonates thereby increasing the risk for supraphysiologic serum bilirubin Various hypersplenic states, including splenic sequestration crisis in sickle cell disease, may result in anemia with accompanying hemolysis and hyperbilirubinemia