This report describes a case in which we treated a patient who developed infective endocarditis in the mitral valve at 28 weeks' gestation. The condition was resolved by performing mitral valvuloplasty 2 days after an emergency cesarean section. Although the patient was in a relatively stable period at 32 weeks' gestation, the mother had an extremely high risk of embolism;thus, emergency surgery was required. We believe that an accurate diagnosis in a timely manner and a valvuloplasty shortly after cesarean section saved the life of the mother and child.