Women suffer from migraines three times more often than men, a statistic that suggests some triggers are determined by gender. Research into biological triggers for women has, for the most part, centered on hormonal changes and the reproductive system.
The Menstrual Migraine
Sixty percent of women who suffer from migraines report an increase in headache frequency during their menstrual period, and for ten to fifteen percent of women they occur only at this time. The most widely held theory suggests that female sex hormones are the cause of menstrual migraines.
Levels of estrogen and progesterone drop sharply towards the end of the menstrual cycle, and estrogen withdrawal may trigger a menstrual migraine. In addition, estrogen levels affect how the brain's serotonin levels function. Serotonin is widely believed to play a role in the perception of headache pain.
It should be noted that the physiological changes that occur during the menstrual cycle are incredibly complex. Many researchers feel that just blaming estrogen levels for increased headache frequency oversimplifies the issue.
Headaches During Pregnancy
Pregnancy often reduces headache frequency. Estrogen levels are high during the second and third trimesters, so the number of headaches a woman experiences during those six months is usually lower than normal. This does not, however, mean that headaches during pregnancy are not a concern. When headaches do occur during pregnancy, treatment is often limited. Medications have to be carefully monitored to avoid possible fetal damage, especially in the first trimester. Some of these medications cannot be used at all during pregnancy.
Although headaches during pregnancy are typically infrequent, a sharp rise in frequency after birth is common. Estrogen levels drop significantly during the postpartum period, and a corresponding increase in headaches is often seen.
Menopause and Hormone Replacement Therapy
Menopause has an affect on headache frequency. Many women report that their symptoms improve as menopause progresses, although women who undergo surgically induced menopause often experience a rise in hormonal headache frequency.
Hormone replacement therapy also has an effect. The added estrogen from hormone replacement therapy can trigger and worsen migraines, although 45 percent of women find that the therapy reduces the number of headaches they experience.
Birth Control Pills
Women who already suffer from hormonal headaches do not, generally, report any change in their headache patterns when they start birth control pills. However, a significant number of women start having headaches after beginning a regimen of oral contraceptives, as compared to first-time sufferers who are not on the pill.
Birth control pills contain small amounts of female hormones. Incidences of hormonal headaches among oral contraceptive users increase during the "placebo" week, when hormones in the pills drop. This drop in hormone levels, although quite small, is suspected to trigger the headaches.
Birth Control Pills and Strokes
Although the exact risk levels have yet to be agreed upon, migraine sufferers who use oral contraceptives may be at an increased risk of developing strokes.
