Pill increases risk of stroke in women with migraines

Women who suffer from migraines are nearly 17 times more likely to have a stroke if they are also on the Pill, new research has discovered.

Researchers have now discovered the alarming effects that factors other than migraine such as the oral contraceptive pill, smoking and high blood pressure have on magnifying the risk.

Researchers from the Imperial College School of Medicine in London have found that between 20 and 40 per cent of strokes in women develop directly from a migraine attack the migraine precipitates the stroke.

The Pill is the factor that most dramatically increases the risk, but migraine sufferers who also smoke are seven times more likely to suffer a stroke, while women with high blood pressure increase their risk three fold.

The new findings are based on research among 291 women aged 20 to 44 years who had suffered a stroke, compared to 736 matched controls.

The risk among Pill users is reduced to around six times if the dose is low, defined as being under 50 mcg. The worst risk is for the woman who smokes, takes the Pill and suffers migraine; her chances of suffering a stroke are 34 times greater than a woman who claims none of these factors.

A woman with migraines but who did not take the Pill, did not smoke and did not have high blood pressure still had a 1.78 times greater risk of having a stroke than a woman who has no migraines. Women with migraines were most likely to suffer an ischaemic stroke rather than a haemorrhagic one (BMJ, 1999; 318: 13-18).