If you're prone to migraines, you may have noticed that you're more likely to experience one right around the time when you start your period. This isn't a coincidence, and no, it's not just fate being cruel. There's a particular kind of migraine known as a "menstrual migraine" which is specifically tied to the menstrual cycle.
"Studies show that migraine is most likely to occur in the two days leading up to a period and the first three days of a period," explains the Migraine Trust, adding that this kind of migraine affects less than 10% of women, though 18% of American women will experience regular migraines. And the cause of these menstrual migraines is tied to hormones, nerves, and the structure of your central nervous system.
The experience of more intense or more frequent migraines before or during your period is likely due to hormonal fluctuations, specifically the lowering of estrogen levels in your body. Throughout the menstrual cycle, hormone levels follow a pattern of rise and fall, and just before your period your estrogen levels are at their lowest, as the body prepares to shed its uterine lining. If you're prone to menstrual migraines, migraine researcher Dr. Markus Dahlem told period app Clue in 2017, you'll likely experience them "on the day of menstruation or within the two following or preceding calendar days."
The relationship between estrogen and migraines is a complicated one, and research is still working out why menstruation can trigger migraine headaches in some people. Estrogen actually has a strong effect on the brain, including on neurons themselves, and it's that link that seems to cause menstrual migraines. A study in 2014 published in Current Opinion in Neurology noted that "as estrogen can extend its impact in a variety of systems, its role in headache is likely multifactorial, including direct cellular and genetic modifications in the CNS [central nervous system], as well as potentially as a result of its effect on mood and pain perception." In other words, lowered levels of estrogen when you're on your period can potentially cause migraines in many different ways, from interactions with the brain to levels of pain tolerance.
However, more clues about menstrual migraines are emerging. A study in 2018 found that the key to estrogen sensitivity and migraines might be the cells around the trigeminal nerve. It's the biggest nerve in the brain, and is the source for sensation in your face, mouth, nose and sinuses. You may have heard of trigeminal neuralgia, a chronic pain condition, in which any stimulus of the nerves in your face can cause extreme pain. The trigeminal nerve is also involved in many migraines.
The study in 2018, published in Frontiers in Molecular Biosciences found that changes in estrogen levels in women appear to make the cells around the trigeminal nerve more sensitive to stimuli. That, in turn, could make people with those sensitive cells more prone to migraines. It's a big potential insight into how estrogen leads to migraine — and why it affects some migraineurs and not others.
Estrogen-related migraines aren't just confined to periods. Fluctuating estrogen levels overall as you approach menopause may also be responsible for more frequent migraines, according to research published in The Journal of Head and Face Pain in 2016; as menstruation ends altogether, the peaks and dips in estrogen can mean migraines are more frequent and intense. The trigeminal nerve might be involved in this too, but research hasn't been done to prove it. People who experience migraines also often find that being pregnant, with its high levels of estrogen, brings relief from migraines, but that they begin again after the baby's born.
The trigeminal nerve might also have another hormone sensitivity which could affect menstrual migraines. While estrogen is a clear culprit, the Migraine Trust explains that prostaglandins, which are released in the first two days of your period, might also cause menstrual migraines. Prostaglandins are released in the body to help the body expel the uterine lining, and are tied to high levels of painful cramps. They're a part of the body's pain response, and it's thought that their higher levels when you're cramping might influence migraines too. A 2013 study published in Current Opinion in Neurology found that injections of particular prostaglandins caused the trigeminal nerve to trigger headaches in healthy people. However, there's still a lot of work to be done to figure out whether there's any connection between prostaglandin levels in menstruation and the occurrence of migraines.
If you experience menstruation-triggered migraines, the Migraine Trust suggests using the NSAID mefenamic acid, which it notes is "an effective migraine preventive and is also considered to be helpful in reducing migraine associated with heavy and/or painful periods." The Mayo Clinic also recommends traditional pain relief like ibuprofen, biofeedback, relaxation exercise and acupuncture, but it's best to talk to your doctor to find the best combination of treatments for your menstrual migraines.