Marked Hyperbilirubinemia in a Patient with Intrahepatic Cholestasis of Pregnancy and a UGT1A1 Polymorphism: A Case Report

A 36-year-old pregnant woman at 34 weeks of gestation, who had been receiving tocilizumab for Takayasu arteritis, presented with pruritus and hyperbilirubinemia. She delivered a healthy infant the day after admission. However, her bilirubin level increased to 32.2 mg/dL. Genetic testing revealed heterozygosity for a uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) polymorphism, and a liver biopsy revealed canalicular cholestasis. The patient was diagnosed with intrahepatic cholestasis of pregnancy (ICP) with UGT1A1 polymorphism, and tocilizumab therapy might have contributed to the marked and prolonged hyperbilirubinemia. Liver histology was useful for the diagnosis of ICP in this case.