The overall stroke rate for women who had migraine with aura was 4.3 per 1000 women per year, according to the results of a 15-year-long study.

Women who experience migraines with aura may be at an increased risk for all major stroke subtypes, according to the results of a large cohort study presented at the 2013 International Headache Conference in Boston on June 30, 2013.
Previous research has shown migraine with aura to be associated with an increased relative risk of stroke, but the new study is the first to evaluate its absolute effect on stroke occurrence and how this compares with the effect of other risk factors.
The researchers identified 27,860 women participating in the Women’s Health Study who were at least 45 years old and did not have any cardiovascular disease at baseline. Participants reported data on migraines throughout the 15-year duration of the study. Although migraines are often self-diagnosed incorrectly, self-reports in the study were considered reliable because the participants were health professionals. Stroke events were confirmed through medical records. Stroke risk was than calculated, adjusting for risk factors such as age, alcohol intake, hormone use, and family history of stroke.
At baseline, 5130 patients reported migraines of any kind, and 1435 reported migraines with aura. Throughout the study period, a total of 528 stroke events occurred: 430 ischemic strokes, 96 hemorrhagic strokes, and 2 strokes of unknown type. The overall stroke rates per 1000 women per year were 1.2 for total stroke, 1.0 for ischemic stroke, and 0.2 for hemorrhagic stroke. Among patients who reported migraine with aura, the overall stroke rate was 4.3 per 1000 women per year. The stroke risk associated with migraine with aura was significantly greater than that associated with other risk factors, including smoking, high blood pressure, diabetes, and family history of heart attack.
The results show migraine with aura to be a strong risk factor for total, ischemic, and hemorrhagic strokes, but the researchers are unsure whether reducing migraine frequency or severity will also reduce stroke risk. For this reason, they suggest that future studies focus on the effects of migraine treatment on stroke risk.