Warning There are no bilirubin levels which are known to be safe or which will definitely cause kernicterus Infants who experience severe hypoxia hypothermia or any serious illness may be susceptible to damage from hyperbilirubinemia.Warning There are no bilirubin levels which are known to be safe or which will definitely cause kernicterus. Infants who experience severe hypoxia, hypothermia or any serious illness may be susceptible to damage from hyperbilirubinemia