References:Migraines(Chinese Version)
American Council for Headache Education http://www.achenet.org

Prevalence of Menstrual Migraine

About 60% of women with migraine note an increased number of headaches in association with their menstrual period. In 10% to 14% of these women, the migraine occurs around the time of the period and at no other time. The term "menstrual migraine" is often used to describe this type of migraine, but the term is not used consistently and it lacks a universally accepted definition. Many headache authorities think the term "menstrual migraine" should be restricted to migraines that occur in women that experience 90% of all their attacks between the two days before and the last day of their menstrual periods.

Causes of Menstrual Migraine

Levels of female sex hormones, specifically progesterone and estrogen, sharply decline in the late phase of the menstrual cycle, just before the onset of the period. Studies have shown that supplemental estrogen given at the time of the natural monthly decline in these hormones delays the onset of migraine until the estrogen level finally decreases. These findings suggest that estrogen withdrawal may trigger migraine in women who are predisposed to migraine. However, falling estrogen levels alone are probably not the only factor involved in menstrual-associated migraine. The density and sensitivity of receptors in the central nervous system that respond to opiate drugs (morphine, codeine, among others) also changes throughout the menstrual cycle.

One explanation for the onset of migraine when estrogen levels drop is that estrogen influences the serotonin receptors, which is believed to be an important part in headache pain. Other factors that may play a role in the development of menstrual migraine include:

1. the relative proportions of estrogen and progesterone;

2. dysfunction of platelets, a component of the blood which contains serotonin;

3. decreased levels of brain magnesium (which increases brain excitability);

4. decreased natural brain endorphines; and

5. increased secretion of prostaglandins (substances that sensitize pain receptors and cause inflammation around the cerebral blood vessels).

Management of Menstrual Migraine

It is common for women to pay more attention to headaches around the time of their menstrual periods, failing to report shorter, milder headaches that occur at other times. Sometimes the fatigue, menstrual cramping, and other symptoms of menstruation reduce the tolerance of headache. Treatment for menstrual migraine can be very successful in some patients and more challenging in others, and success depends on an accurate diagnosis. Most common treatment inculdes pharmacotherapies, however, some also rely on nonpharmacologic therapies.

[Some complications or challenges exist in treating patients with migraine associated with menses. For example, some women may use treatment intended for use only once a month to treat other headaches, resulting in medication overuse and harmful side effects. For the more difficulty to manage menstrual migraine, sometimes hormone manipulation is tried, although it is not traditionally first-line therapy.]

Pharmacological (medication) treatment of menstrual migraine is generally complex, since many treatment strategies are available. Patients may be managed by treating each attack when it starts. These medications are known as "acute medications." Some sufferers require preventive therapy because their attacks are very frequent, severe, or disabling.

Acute Treatments

Triptans

The efficacy of triptans (naratriptan, rizatriptan, sumatriptan, zolmitriptan) as an acute therapy for menstrual migraine has been the subject of great interest. Naratriptan, with its slower onset, longer duration of action and lower recurrence rate, is thought to be helpful for menstrual migraine. Zolmitriptan has been shown to be equally effective in migraine occurring in relation to the menstrual period as in migraine occurring at other times. One small, open-label study showed sumatriptan 25 mg three times a day was effective for mini-prophylaxis of menstrual migraine. It is likely that rizatriptan may also prove to be effective in treatment of menstrual migraine.

Ergotamine, Ergot Combinations, Ergot Alkaloids (Dihydroergotamine)

Acute therapy with ergotamine preparations (oral, rectal, or intranasal), and dihydroergotamine (intranasal, intramuscular, or intravenous) are effective for some women, although they often need to take these agents with another medication to prevent the side effect of nausea.

NSAIDs & Analgesics

Nonsteroidal anti-inflammatory medications (NSAIDs) such as ibuprofen or naproxen sodium, play an important role in the treatment of menstrual migraine because they affect prostaglandins, substances that may cause cramping as well as adding to the headache response. One combination analgesic (acetaminophen, aspirin, and caffeine) also has been reported to be effective in treating migraine associated with menses. NSAIDs and other analgesics may be used as either an acute treatment at headache onset or to prevent migraine if taken regularly staring a few days before the anticipated onset of the headache, and continued through the menstrual period. If the period is regular and the headache occurs in a predictable way, it may be worth trying a scheduled dose of an NSAID. This may begin 24 hours before the expected onset of the headache (which may differ from onset of the period) and continue for the expected duration of the headache. Importantly, these agents should not be used in patients who have contraindications for using NSAIDs (hyperacidity syndromes such as ulcer, gastrointesinal esophogeal reflux disease, the triad of aspirin sensitivity, nasal polyps, and asthma and kidney disease); patients should consult their physician prior to using any medications.

Hormone Therapy

Hormone therapy is usually considered only after these other measures have failed. Taking estrogen during the period, either orally or with the estrogen patch, has helped some women. Estradiol skin patches or gel started 48 hours before the anticipated start of the migraine attack and continued daily for 7 days is well tolerated and effective for some women with menstrual migraine. Estrogen tablets do not seem to work as well, possibly because they do not maintain steady hormone levels in the blood. Side effects can include irregular menstrual periods, and for some, this may make treatment unacceptable.Continuous low-dose oral contraceptives (OCs) reduce the hormone fluctuations that trigger migraine in susceptible women, and can also be considered for patients with refractory (difficult-to-treat) menstrual migraine. Continuous low-dose OCs often are used for endometriosis or other conditions, as in migraine, where using alternating doses (cycling) of estrogen levels can cause problems. Other hormonal treatments are more aggressive (e.g., tamoxifen, bromocriptine mesylate, danazol and gonadotropin-releasing hormone [GNRH] therapy with add-back estrogen) and have reportedly been helpful for some patients with refractory migraines. Some of these medications may be effective against menstrual migraine, but they have many unpleasant side effects. For the most severe cases of menstrual migraine, GNRH drugs have been tried. GNRH stops the ovaries from producing female sex hormones (estrogen and progesterone; this is also know as medical menopause). None of these treatment regimens have been well studied, and they are not frequently used.

Preventive Treatments

If an effective medication is not found to treat headache when it starts, patients may use daily preventive medications including (listed alphabetically):

1. anticonvulsants,
2. beta-blockers,
3. calcium channel blockers,
4. NSAIDs,
5. tricyclic antidepressants, and
6. serotonergic agents (including triptans)

Clinical benefits have also been reported for zolmitriptan and thought to be effective for naratriptan.

For some patients, the doses of daily preventive medications can be increased around the time of the menstrual period to cope with an expected menstrual headache, and some doctors even advocate the use of preventive migraine medications only during these time (referred to as "pulsed prophylaxis"). Again, controlled clinical studies have not been done, but physicians will generally prescribe preventive medications based on expert opinions and their own clinical experience.

Nonpharmacological Techniques

For many patients, nonpharmacological therapies can help reduce frequency and severity of attacks. These treatments include biofeedback, relaxation therapy, hypnosis, meditation, physical manipulation (osteopathic manipulation) and cognitive behavioral training. Also, some anecdotal work has been done studying the effects of surgery on migraine.

Acute

Several treatment strategies help migraine sufferer reduce the discomfort and other symptoms of an attack. These include resting, using icepacks or heat packs (on the face, head or neck), relaxation techniques, sleeping, adjusting the lighting in a room, and reducing noise.

Nonpharmacological Techniques

Nonpharmacological techniques used preventatively have been shown to benefit some migraine sufferers. Reductions in severity or frequency of migraine have been reported for cognitive biofeedback training, biofeedback therapy, relaxation therapy, stress management, and acupuncture. These approaches may require a major commitment since multiple training sessions, follow-up visits, and education sessions are required, depending on the methods used.

Lifestyle Changes

Identifying and avoiding aggravating factors is one way for patients to reduce the frequency or severity of migraine attacks. This approach requires close monitoring of attacks and identifying aggravating factors such as stress, foods such as red wine or coffee, skipping medications, and sleep pattern changes. For some, this requires discipline and lifestyle changes and regular use of a diary. More scrupulous avoidance of known headache triggers may be necessary around the time of the period and less important during the rest of the month. For example, some women may need to be careful about getting enough sleep, eating regular meals and avoiding alcohol prior to the start of menstruation if they know they are more vulnerable to headaches at this time. For many women, regular aerobic exercise can help.

Surgery

There is no evidence that hysterectomy and oophorectomy (surgical removal of the ovaries) are useful in treating menstrual migraine. Women who undergo these procedures face the risk of major surgery followed by decisions about hormone replacement therapy, which can also aggravate headache in some patients.

Menstruation as a Trigger of Migraine

In the physician's and patient's eagerness to identify and treat headache triggers, they must be careful not to overemphasize the role of menstruation as a headache trigger. Recent trials of headache medications show no differences in headache severity or response to treatment for patients whose headaches are associated with menstruation compared to those whose headaches are not associated with menstruation. This information conflicts with the general observation that headaches associated with menstruation last longer, are more severe, and are more difficult to treat than other headaches.

What accounts for this difference between perception and reality of migraine severity and frequency during menstruation? Menstruation is a normal event but one which is conspicuous and which carries a great deal of cultural and emotional significance. Events, including headache, which occur in relation to the menstrual period are more likely to be remembered and may be attributed to the period even if that association is by chance alone.

When one considers that the average menstrual period lasts 4 to 5 days and occurs once every 28 days, it becomes clear that a significant number of headaches that occur in relation to the menstrual cycle do so by chance alone. In addition, headaches that occur with other symptoms of menstruation (such as abdominal cramping) may seem more troublesome not because they are more severe but because, together with other symptoms, they are more difficult to tolerate.

Overemphasis on menstruation as a trigger may increase the distress of patients by making them feel they are at the mercy of their hormones, and that headaches with menstruation are inevitable. A more useful approach to the problem of menstrual is to:

• recognize hormone fluctuations as only one of many triggers, and
• assume an active role in managing headaches.