Migraine - Causes of migraines

The exact cause of migraines is unknown, although they are thought to be the result of abnormal brain activity temporarily affecting nerve signals, chemicals and blood vessels in the brain.

It's not clear what causes this change in brain activity, but it is possible that your genes make you more likely to experience migraines as a result of a specific trigger.

Migraine triggers

Many possible migraine triggers have been suggested, including hormonal, emotional, physical, dietary, environmental and medicinal factors.

Hormonal changes

Some women experience migraines around the time of their period, possibly because of changes in the levels of hormones such as oestrogen around this time.

These are known as menstrual-related migraines and they usually occur between two days before the start of your period to three days after. Some women only experience migraines around this time, but most experience them at other times too.

Many women find their migraines improve after the menopause, although the menopause can trigger migraines or make them worse in some women.

Emotional triggers:

stress
anxiety
tension
shock
depression
excitement

Physical triggers:

tiredness
poor quality sleep
shift work
poor posture
neck or shoulder tension
jet lag
low blood sugar (hypoglycaemia)
strenuous exercise, if you are not used to it

Dietary triggers:

missed, delayed or irregular meals
dehydration
alcohol
the food additive tyramine
caffeine products, such as tea and coffee
specific foods such as chocolate, citrus fruit and cheese

Environmental triggers:

bright lights
flickering screens, such as a television or computer screen
smoking (or smoky rooms)
loud noises
changes in climate, such as changes in humidity or very cold temperatures
strong smells
a stuffy atmosphere

Medication:

some types of sleeping tablets
the combined contraceptive pill
hormone replacement therapy (HRT), which is sometimes used to relieve symptoms associated with the menopause