What are the causes of migraine headaches? I have 2/week and want to see what I can do to proactively address it besides sumatriptan after I get one.

Migraines. Migraines are believed to be caused by inborn abnormalities of the brainstem that cause a process of cerebral neuronal spreading depression that begins in the occipital lobe leading to neurogenic inflammation of meningeal arteries, which is painful. My general rule is that when headaches occur more than 1-2 days per week I add preventative meds to the abortive meds.