[A case of multiple sclerosis with relapses during the third trimester of pregnancy].

We report a 31-year-old woman with a relapse of multiple sclerosis during the third trimester of pregnancy. She had been treated palliatively after the relapse until occurrence of a new symptom and new lesions on MRI, and then she had Cesarean section. After surgery, steroid pulse therapy was started and the symptoms and lesions on MRI resulted in improvement. As a strategy to treat patients with multiple sclerosis in their third trimester of pregnancy, it is appropriate to evaluate disease activity using MRI and to start steroid pulse therapy after delivery.