A 32-year-old woman was diagnosed with autoimmune hemolytic anemia (AIHA) at 12 weeks of a pregnancy examination and followed up closely without treatment. At 40 weeks of gestation, she underwent emergency caesarean section because of premature rupture. On postoperative day one, the patient exhibited worsening hemolysis and tachycardia and developed high-output heart failure; she was diagnosed with Basedow disease based on the tachycardia pattern and thyroid storm based on the presence of hyperthyroidism, fever, tachycardia, and heart failure. She was administered thiamazole and potassium iodide, which improved her thyroid function, hemolytic anemia, and heart failure. AIHA is rarely associated with Basedow disease, and hemolytic anemia can be aggravated by hyperthyroidism. In pregnant women with AIHA, management of hyperthyroidism is crucial as delivery can lead to thyroid storm.