I started getting migraines when we moved from NY to Colorado -about 8 years ago.  I was told it could have something to do with the altitude -pressure and such; and I was under what I thought was a lot of stress at the time (moving away from home, new job, in-laws...).  The first migraine incident happened while I was at work and they ended up taking me to the ER.  I get auras and have problems with speech (in my head I know what I want to say, but it certainly doesn’t come out that way).  At work, my friends were afraid I was having a stroke.  After that initial episode, I got them about once every other month for a year, and was put on meds for it.  After that year, life calmed down for me, and I didn’t have them again until I got pregnant with my first son (4 years ago). My OB said the hormones during pregnancy definitely were at fault for them then.