Upwards of 70 percent of women suffer #migraines associated with their menstrual flow and I can't tell you how grateful I am to not be among these women, because having suffered only a few true migraines in my life, I can tell you with complete confidence that there is no way I could manage these on a regular basis and maintain any sense of productivity or even sanity. Migraines associated with one's menses, which I have not experienced, are said to be the more severe migraines experienced, so again, I simply can't imagine.
Migraines related to your cycle are the result of a drop, a fairly dramatic drop in fact, in your #estrogen levels. This happens twice in your cycle, once just after ovulation and again just before your flow. This drop drags your serotonin levels down too, which is most likely why the pain occurs.
Most women who experience hormonal migraines get them premenstrually, but others get them after ovulation, and some suffer both. If you have migraines in general, then the hormonal changes in your cycle certainly predispose you to more migraines.
These reflect a hormonal imbalance and because they are often incapacitating, severe, last longer than typical migraines, and are more difficult to treat, this really is a significant women's healthcare issue that should be a clinical priority to resolve.