Migraine - Causes 

Causes of migraine 

Migraines are thought to be caused by changes in the chemicals of the brain.

In particular, levels of a type of chemical called serotonin decrease during a migraine.

Low levels of serotonin can make the blood vessels in a part of your brain spasm (suddenly contract), which makes them narrower. This may cause the symptoms of aura. Soon after, the blood vessels dilate (widen), which is thought to cause the headache. The reason for the drop in serotonin is not yet fully understood.


Some scientists believe that fluctuating levels of hormones are closely linked to the cause of migraines.

Some women who experience migraines say they are more likely to have an attack around the time of their period. This is known as a menstrual migraine. Just before women have their period, levels of the hormone oestrogen fall.

Women can have menstrual migraines from two days before to three days after the first day of their period. About 1 in 7 women who have migraines only have an attack around the time of their period. This is known as a pure menstrual migraine. Around 6 in 10 women with migraines have attacks at other times too.

Other migraine triggers

Many factors have been identified as triggers for a migraine. These triggers include emotional, physical, dietary, environmental and medicinal factors. They are outlined below.

Emotional triggers

These include:

  • stress
  • anxiety
  • tension
  • shock
  • depression
  • excitement

Physical triggers

Physical triggers include:

  • tiredness
  • poor quality of sleep
  • shift work
  • poor posture
  • neck or shoulder tension
  • travelling for a long period of time
  • low blood sugar

The menopause can also trigger migraines.

Dietary triggers

Dietary triggers include:

  • lack of food (dieting)
  • delayed or irregular meals (see below)
  • dehydration
  • alcohol
  • the food additive tyramine
  • caffeine products, such as tea and coffee
  • specific foods such as chocolate, citrus fruit and cheese

When you do not eat regular meals, your blood sugar levels fall. If you then eat a sugary snack, blood sugar levels shoot up. These ‘peaks and troughs' could trigger migraine attacks.

Environmental triggers

Environmental triggers include:

  • 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


Some medicines can trigger migraines, including:

  • some types of sleeping tablets
  • the contraceptive pill
  • hormone replacement therapy (HRT), which is sometimes used to treat the menopause 

Page last reviewed: 14/05/2012

Next review due: 14/05/2014


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The 2 comments posted are personal views. Any information they give has not been checked and may not be accurate.

peaceflower said on 29 March 2013

Lynn, I have had fatigue since I was in my teens. I have had four children and found after my second that I was so tired alot of the time that I couldn't stand up for long. After my fourth child was born, four years ago I had what was thought to have been a stroke, but after a night in hospital and various scans I was told I had atypical migraine. I was given various medications by a consultant and then told that if I had the migraines 2 days of the month instead of 28 days, it would be easier to treatt me. Fromm that time until now I have had episodes mos days of feeling weighed down. I cut gluten out of my diet completely about 2 years ago and found myself better able to function. Since then I have had times when I have become very breathless, with weak muscles - even making speech difficult. I saw an allergy specialist this week who told me to take antihistamine daily. I have experienced being in a supermarket and finding it increasingly difficult to manage walking and breathing. The doctor described it to me as possibly being low blood pressure, brought on by an allergic reaction to wheat/gluten. I am being tested this week for allergy to wheat and gluten (not coeliac disease) as it affects my work and social life.

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Lynn Powell Watts said on 18 October 2012

I have had migraines, headaches and fatigue since I was 19 and have tried many remedies. I started the Dukan lo-carb diet at the beginning of this year and have almost eliminated the problems. I found a small piece of anecdotal research from other women who had gone on the Atkins lo-carb diet and benefited from the reduction or elimination of migraines. I would like to know if anyone is seriously looking into this as a possible solution and why it might work.

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