Baking Soda

HI All. My girlfriend has migraines so I have an interest. I'm curious if anyone has used sodium bicarbonate for migraines and if they had a good result. My girlfriend started taking a teaspoon of bicarb when she wakes up in the morning about 3 weeks ago. She had continuous migraines for 6 weeks before that. After starting the bicarb they started subsiding but she still has a sinus head ache. Its been 9 days since her last migraine. Any input will be appreciated. We are aware of possible stomach issues but that has not been a problem so far and she is now taking one half teaspoon of bicarb in the am to keep her bicarb level up. We have run out of money for doctors and morphine. I am thinking I will suggest to her to stop taking the bicarb unless she feels a migraine coming on.