A stroke occurs when there is an interruption to the blood supply to the brain, either due to a blockage (ischaemic stroke) or due to local bleeding (haemorrhagic stroke).
People who suffer with certain types of migraines are thought to have a slightly higher risk of experiencing a stroke.
Having migraine with aura is believed to double the risk of ischaemic stroke, and the risk is higher in women than it is in men, and further increased in people aged under 45, those who smoke and women who take the contraceptive pill.
It is also thought that the risk of haemorrhagic stroke might be increased in women under the age of 45 years who have migraine with aura, though more research is needed.
However, it is important to remember that this risk of having a stroke in younger adults is still generally very low, even in those who have migraine with aura, because younger people generally have fewer cardiovascular risk factors such as furring of the arteries.
Occasionally, a migrainous stroke may occur. This is when a migraine with aura symptoms fails to resolve, and symptoms persist. The most common symptom of a migrainous stroke is a visual symptom known as homonymous hemianopia, a condition where the sufferer can only see out of the right or left side of each eye.
The involvement of blood vessels in both migraine development and stroke may be the reason for the link between the two conditions. In addition, vomiting during a migraine can cause lead to dehydration, which may make blood clots more likely to occur. If you suffer with migraines, it is important to keep other risk factors – such as cardiovascular health – under control.
A fact sheet about migraines and risk of stroke is available from the Stroke Association.