Crispy, if the migraines are hormone related then hormone manipulation is the first line of defence but if that stops working or is not possible, propranolol is next on the list but a high dose is usually needed - I take 200mg every day but you can go as high as 320mg.
After that a TCA antidepressant but if you don't want to switch ADs, the next step is to add in a calcium channel blocker. After that you would need to look at anticonvulsant medication but hopefully the propranolol will work on its own.