Women, Hormones & Headaches
Dr Anne MacGregor says that many women are prone to headaches around the time of their periods, whether or not they also suffer from migraine.
There are many pleasures in being a woman although it has to be said that some effects of female sex hormones are not always enjoyable. For example, many women are prone to headaches around the time of their periods, whether or not they also suffer from migraine. Studies also confirm that migraine is three times more common in women than men during the reproductive years, periods being a common trigger. Not surprisingly, female sex hormones are thought to play a major part in this difference between the sexes.
A Swedish doctor, Bo Bille, was one of the first people to undertake an epidemiological survey of migraine, which he started in the 1950s. He found that both sexes were equally likely to have migraine until the age of 11, after which time girls were affected more than boys. Other studies have confirmed that a first attack of migraine occurs within a year of the first menstrual period. Once migraine has been initiated, attacks are likely to recur although the frequency and severity of migraine varies considerably throughout an individual’s lifetime. Migraine usually becomes less frequent in both sexes after the age of 55.
Migraine and menstruation
A recent study of women attending the City of London Migraine Clinic showed that nearly 50 per cent of women felt that their migraine was more likely to occur around the time of menstruation. For many women, migraine had not been triggered by menstruation in the early years, with regular ‘menstrual’ attacks only becoming apparent during their 30s or early 40s.
In our study, the peak time for migraine during the menstrual cycle was within a couple of days before the start of a period and the first couple of days of bleeding. Although many women would also experience attacks at other times of the month as well, just under 10 per cent of women only had these ‘menstrual’ attacks with no migraine at any other time of the cycle. In all women, oestrogen levels drop just before a period as part of the normal menstrual cycle. It seems that the small group of women with exclusively ‘menstrual’ migraine may be susceptible to this natural hormone drop which, for them, can trigger attacks just before the start of a period.
However, oestrogen is not the only hormone responsible for ‘menstrual’ migraine. Other studies have shown that women who notice migraine more often occurring during the first few days of bleeding may be susceptible to the hormone prostaglandin that is released during menstruation.
Hormonal changes can also increase the effects of non-hormonal triggers, making women more susceptible to the effects of alcohol or missed meals around period time.
What can you do to help yourself?
The first thing is to keep a record of your headaches and periods. This helps to establish the exact relationship between migraine and different stages of the menstrual cycle. Note if your period is heavy or painful and how long it lasts. After a few months look at the records and see if there is any pattern.
If your attacks always occur a week or two before your period, try eating frequent carbohydrate snacks and discuss with your chemist about any supplements you can take to help premenstrual symptoms. Try to eliminate any additional non-hormonal triggers around period time. These include vitamin B6, magnesium and evening primrose oil.
Treat migraine attacks with 900-1000mg soluble or mouth dispersible aspirin every 4-6 hours, or ibuprofen 400-800mg every 6-8 hours, dissolving soluble tablets in a glass of lemonade or other sweet fizzy drink.
How can the doctor help?
If simple painkillers are not effective to control migraine symptoms, your doctor can prescribe specific migraine drugs, including the ‘triptans’. If attacks are monthly and respond to such treatment, this may be enough to give you control.
If your diary card shows frequent migraine throughout the month, this suggests that non-hormonal triggers also play an important role. Consequently hormone treatment will have a limited effect and standard preventive management, including daily preventive drugs, is often more effective.
Premenstrual migraine, occurring just a couple of days before the start of a period may be due to the natural fall in oestrogen that occurs at this time of the cycle. These attacks may be prevented by oestrogen supplements such as 100 microgram oestradiol patches used from 3 days before the start of menstruation for a total of about 7 days.
This regimen should not be confused with hormone replacement therapy as it is only supplementing the oestrogen levels at a time that they naturally fall and is not replacing oestrogen throughout the cycle. For hormone replacement therapy it is usually necessary to prescribe courses of an additional hormone, progestogen or progesterone. This is not necessary for women treating menstrual migraine who still have regular periods since they will produce their own natural progesterone in last two weeks of the menstrual cycle. If there is any doubt, a simple blood test taken 7 days before a period is expected to start will confirm this.
For migraine only during the menstrual flow, particularly if periods are also painful or heavy, it may be worth trying a drug that reduces levels of the hormone prostaglandin. The most commonly used drug, which has this effect, is mefenamic acid, available on prescription. It should be taken in a dose of 500 mg three to four times daily from the start of the menstrual bleed for up to 7 days.
