- Migraine is common, affecting 18 per cent and 6 per cent of the female and male US population, respectively.
- About 80 per cent of British women use the combined oral contraception pill (COCP) at some time between the ages of 16 and 24 years.
- Migraine is the most common type of headache in young adults, affecting as many as one in four US women by their mid-to-late 30s.
- A potential association between migraine and risk of stroke is an important public health concern, especially in young women who use oral contraceptives.
What is the evidence?
- A meta-analysis of 14 studies found that the use of low-dose oral contraceptives was associated with a doubling of the risk of cardiovascular disease (CVD) (J Clin Endocrinol Metab 2005; 90: 3,863-70).
- Women who suffer from migraines with aura have an increased risk of ischaemic stroke. One study found that these women had twice the risk of CVD compared with women without a history of migraine (JAMA 2006; 296: 283-91). Interestingly, women who suffer with migraine without aura had no increased risk.
- The results of a systematic review and meta-analysis also strongly suggest that migraine is an independent risk factor for stroke (BMJ 2005; 330: 63-4). The increased relative risks of ischaemic stroke were 1.8 in migraine without aura, 2.3 in migraine with aura and 8.7 in women who suffer with migraine who take the oral contraceptive pill.
- A recent study showed that probable migraine with visual aura was associated with an increased risk of stroke, particularly among women without other medical conditions associated with stroke. Oral contraceptive use markedly increased the risk of probable migraine with visual aura (Stroke 2007; 38: 2,438-45).
- A review has found increasing evidence that migraine with aura is not only a risk factor for ischaemic stroke but also for MI and other ischaemic vascular events (Curr Opin Neurol 2007; 20: 310-9).
Implications for practice
- Prolonged exposure to low-dose oral contraceptives to those women at higher risk of CVD might significantly increase the incidence of cardiovascular outcomes and alternative contraception might be preferable.
- Given that use of oral contraceptives is common in young women, the potential risk of stroke among women with migraine who are also users of oral contraceptives must be further investigated.
- It might be that we should be more aggressive in our primary prevention of CVD in migraine sufferers. Dr Louise Newson is a GP in the West Midlands and author of 'Hot Topics for MRCGP and General Practitioners' PasTest 2006
- Migraine is common in young women.
- Migraine with aura increases the risk of stroke and CVD.
- The COCP is contra-indicated for patients who have migraines with aura.