Migraines may be caused by changes in the brainstem and its interactions with the trigeminal nerve, a major pain pathway.
Imbalances in brain chemicals — including serotonin, which helps regulate pain in your nervous system — also may be involved. Researchers continue to study the role of serotonin in migraines.
Migraine headache triggers
Whatever the exact mechanism of the headaches, a number of things may trigger them. Common migraine triggers include:
Hormonal changes in women. Fluctuations in estrogen seem to trigger headaches in many women with known migraines. Women with a history of migraines often report headaches immediately before or during their periods, when they have a major drop in estrogen.
Others have an increased tendency to develop migraines during pregnancy or menopause.
Hormonal medications, such as oral contraceptives and hormone replacement therapy, also may worsen migraines. Some women, however, may find their migraines occur less often when taking these medications.