A 32-year-old woman at 16 weeks of pregnancy was diagnosed with acute type A aortic dissection and severe aortic regurgitation. Aortic valve and aortic arch replacement was successfully performed under circulatory arrest with deep hypothermia. After the operation, she was diagnosed with Loeys-Dietz syndrome. At 36 weeks of gestation, the patient underwent a cesarean section and delivered a healthy baby.