Oral Contraceptive Use and Acute Ischemic Stroke Risk in Patients with Moyamoya Disease

To investigate whether oral contraceptives induce acute ischemic stroke in patients with moyamoya disease. We retrospectively reviewed female patients with moyamoya disease who were taking oral contraceptives during their reproductive years (12-49 years of age) at the time of diagnosis or during follow-up. The patients' detailed clinical history, including the time course of oral contraceptive usage and acute ischemic stroke occurrence, was evaluated. For patients with radiological evidence of acute ischemic stroke, the imaging pattern of stroke was assessed to investigate the underlying mechanisms. Among 589 female patients, 12 patients took oral contraceptives at some point during the period from 2012 to 2023; 5 patients were taking oral contraceptives at the time of diagnosis, and 4 of them were diagnosed with moyamoya disease after acute ischemic stroke. Among the 7 patients who started oral contraceptives during follow-up, 2 patients developed acute ischemic stroke several months after starting oral contraceptives. Notably, none of the hemispheres that developed acute ischemic stroke previously underwent revascularization, and none of the 5 hemispheres with prior revascularization developed acute ischemic stroke. The imaging pattern of acute ischemic stroke in 7 patients suggested the contribution of a thromboembolic mechanism. Oral contraceptives may increase the risk of acute ischemic stroke via thromboembolic mechanisms in patients with moyamoya disease, but its risk might be manageable in hemispheres with prior revascularization and stable disease conditions for years. Active education of patients regarding the possible risk of oral contraceptives and close communication with gynecologists seem necessary to provide the best treatment strategies for female patients with moyamoya disease who require contraception or treatment of menstrual disorders.