I think my migraines are hormone induced. My first was when I stopped breastfeeding and went back on the Yasmin combined pill (and boy, was it a doozy of a migraine, ended up in hospital with that one), after that I got one monthly, the day before my period started until I stopped taking the pill. I was migraine free for a while, until getting pg with DD2, and had two early on in the first trimester. I then had another migraine when I stopped breastfeeding DD2. So generally, it seems I get them when there is a huge hormone shift. But yeah, migraines suck.