Many women who suffer from headaches notice a connection between them and their menstrual cycle. According to the "Journal of the American Medical Association," 50 percent to 60 percent of female migraine sufferers are affected by "menstrual migraine"—migraine associated with the shift in hormone levels that occurs immediately before and during menstruation. The hormone primarily responsible for these headache-inducing fluctuations is estrogen. Regardless of a woman's stage of life—whether she is menstruating, pregnant or entering menopause—estrogen fluctuation can be the cause of debilitating headaches.
The Headache-Estrogen Connection
Eighteen percent of women suffer from migraine headaches, compared to only 6 percent of men, suggesting a hormonal link between migraines and gender.
Almost 40 years ago, scientists hypothesized in the medical journal "Neurology" that because women suffer from more headaches around the time of menstruation, sharply declining estrogen levels at the time of menstruation are likely the cause of such headaches. They showed that when women undergoing in vitro fertilization were treated with drugs that decrease estrogen levels as part of their treatment protocol, 82 percent of the women experienced debilitating headaches.
How Does Estrogen Cause Headaches?
In recent years, scientists have attempted to find a mechanism to explain how fluctuations in estrogen can cause headaches. In animal studies, changes in estrogen levels affect the expression levels of genes that are associated with inflammation and neurological pain. These studies suggest that the drop in estrogen before menstruation might influence inflammation and neurological pain.
Experiments published in the "Journal of Clinical Investigation" demonstrate that estrogen affects blood vessels through nitric oxide release. Women who suffer from migraines show a heightened activation of the nitric oxide pathway before menstruation compared to those who don't suffer from migraines. Therefore, changes in blood vessels in response to an increase in nitric oxide release caused by a drop in estrogen might result in headaches around menstruation.
Menstruation and Birth Control
The connection between estrogen and headaches is most apparent immediately before and during menstruation. Because the menstrual cycle is a predictable monthly event, it is possible to take preventative headache medication immediately preceding your period. Interestingly, for many women, menopause cures their estrogen-related headaches because after menstruation ceases, hormone levels remain steady.
Sometimes changes in estrogen levels from birth control pills can also cause headaches. Many women actually experience an improvement in hormonally related headaches when they start birth control pills, but for others the pills seem to be the culprit. If you suspect your birth control might be causing your headaches, ask your doctor to change your form of birth control.
Changes in estrogen levels during pregnancy can cause headaches for some women but cause fewer headaches in others. Estrogen rises dramatically at the beginning of pregnancy and then remains constantly high throughout. As a result of constantly sustained estrogen levels, many migraine sufferers experience relief from migraines during pregnancy. To the contrary, tension headaches might increase. If you are pregnant and suffering from headaches, ask your physician which medications are safe for you to take.
The Mayo Clinic recommends applying ice, massaging muscles at the back of the head, neck and shoulders, and taking over-the-counter pain relievers as first lines of defense against estrogen-related headaches. If these recommendations aren't effective, ask your physician about prescription pain medications. Some of these medications are taken preventatively in the days preceding menstruation, but others are taken when you feel a headache coming on.