People who experience migraines with aura - temporary visual or sensory disturbances - are twice as likely to suffer a stroke, according to the BMJ.
It reports a study at Harvard Medical School that claims to have confirmed a link that is most common among young women who also smoke and use contraceptives containing oestrogen.
The research team reports that there is no evidence of an increased risk of stroke among people who experience migraines without aura.
The report says: “Factors that further increased the risk of ischaemic stroke (caused by clots, accounting for 80% of strokes) were age less than 45 years, smoking, and use of oral contraceptives.
“Young women who have migraine with aura should be strongly advised to stop smoking, and methods of birth control other than oral contraceptives may be considered.
“This increased risk is only apparent in those who have migraine with aura and not in those with migraine without aura, the relative risk being double.”