Migraines and pregnancy

So we've been trying for 2 years, recently diagnosed with PCOS. Finally started metformin in May and Letrozole in September. I've always had migraines and I've taken imitrex for them, however, since we've got a diagnosis and are hoping to get a BFP in the next few months I want to avoid any medication that aren't supposed to be taken while pregnant. Long story short, what have you used as an alternative for migraines?