Migraine and a woman’s monthly cycle

Are sex hormones involved?

The Austrian Broadcasting Corporation's science magazine program asked Christian Wöber, head of the headache outpatient clinic at Vienna General Hospital, Austria’s largest university hospital. Christian Wöber confirmed the difference in migraine burden between the genders. Reporting from the front lines of headache management, Wöber says he does in fact see indications in his female patients that sex hormones play a role in triggering migraine attacks. The natural changes in hormone levels in the menstrual cycle may be a factor, Wöber believes.

Another observation seems to confirm this suspicion: many women with lifelong migraine notice an improvement after the “change of life” (menopause). And many women with migraine notice an improvement when they get pregnant. Wöber suspects that female hormones are involved in both cases. Estrogen levels are consistently low after the menopause and consistently high during pregnancy. In both of these life stages, hormones do not fluctuate in the same way as in a "normal" menstrual cycle. This led some scientists to suspect that the more stable hormone situation might be why the migraine burden improved.

Natural hormone fluctuations regulate the menstrual cycle

An ordinary menstrual cycle looks like this: It begins on the first day of your period (menstruation). This is when the uterine lining built up during your previous cycle is shed from your body. At the beginning of each cycle, the level of estrogen (a hormone in your blood) is relatively low. The estrogen level gradually rises when small sacs (follicles) in your ovaries ripen and the egg cells (oocytes) in your follicles start maturing. This stage is called “oocyte maturation”.

As estrogen levels rise, the lining of your uterus thickens and receives a rich supply of blood and nutrients that will provide an ideal nest for a (possibly) fertilized egg to grow. Estrogen levels continue to rise until the ripening egg is ready for release. At ovulation, the follicle bursts and the mature egg is released from the ovary. It now travels through the fallopian tube toward the uterus. With this process, the cycle enters a new stage called the “luteal phase”. The "corpus luteum" forms from the ruptured follicle. The corpus luteum starts producing progesterone, another hormone. Progesterone thickens and preserves the uterine lining previously built up under the influence of estrogen.

Östrogen wirkt auf bestimmte Nerven

If the egg is not fertilized, the corpus luteum breaks down and progesterone production comes to a halt. As the levels of the two hormones fall, the blood and tissues lining the uterus start to come loose. Your body sheds this material during your next period and a new menstrual cycle begins.

Observations from science

In 2018, a Spanish research team reviewed the existing scientific evidence on the role of sex hormones in triggering migraines. The review showed that women with migraine in their fertile years with a normal menstrual cycle are much more likely to have a migraine attack in the days around menstruation. This is approximately when estrogen levels fall and progesterone levels rise.

However, the researchers point out that the role of the sex hormones in triggering migraine is very complex and not well understood yet. More research is needed, long-term studies in particular.

Estrogen affects certain nerves

The studies also discovered connections that made scientists suspect something else: that the changes in estrogen levels during a woman’s monthly cycle might affect cells in a nerve in the brain called the trigeminal nerve. The trigeminal nerve is thought to play an important role in causing migraine attacks. Researchers believe that some nerve signals from this nerve trigger inflammation in the blood vessels of the meninges (the membrane layers that protect the brain). This might cause the typical pulsating, throbbing pain of a migraine headache.

Current understanding and future outlook

Many experts believe there is enough proof that decreasing estrogen levels are linked to higher rates of migraine. But experts disagree on whether hormone treatment would improve the situation. The questions around the exact impact of sex hormones on numerous bodily functions in general, and migraine occurrence in particular, are too complicated.

At least there is hope that a more precise understanding of the processes driving menstrual migraines will result in more effective ways to combat this type of migraine.

But it looks like the “migraine gender gap” will be with us for quite a while yet. Much research remains to be done in this area.