Hyperthyroidism in pregnancy may pose a great threat to maternal and fetal health. The risk of hyperthyroid heart disease (HHD), even heart failure, is significantly elevated in pregnant women.To investigate the clinical characteristics, prognosis, and therapy of HHD in pregnant women.We searched the patient registry data at West China Second University Hospital of Sichuan University in Chengdu, China, following the approval by the Ethics Committee. We retrospectively analyzed the clinical characteristics of pregnant women diagnosed with HHD. The medical records of women with HHD during pregnancy from January 2012 to December 2017 were obtained from the electronic medical records system. All the included patients were followed in outpatient clinics and by telephone interviews until October 2018.A total of 155 patients were diagnosed with thyrotoxicosis, of whom six were diagnosed with HHD. Three of them had regular antenatal care. Two patients were complicated with acute heart failure attacks, and one of them had a stillbirth. Both of these patients had a long history of Graves' disease with poor treatment compliance. Treatments of precipitating factors such as the control of infection could relieve the symptoms and prolong gestation for a better prognosis. Hyperthyroid heart failure could be controlled with aggressive diuretics and management of the coexisting complications. Intense monitoring and timely anti-heart failure treatment were crucial in patients with severe cardiac damage. Our findings indicated the importance of regular antenatal care and treatment adherence in patients with hyperthyroidism.The timely and accurate diagnosis of HHD and the implementation of effective management are important for a better prognosis in pregnant women with HHD. Improvement in patients' awareness of thyrotoxicosis is needed.