My mum suffers from abdominal migraines (she has never had a headache migraine, although I was prone to them as a teenager). She doesn't get them so much anymore, by far her biggest trigger is stress. They were at their peak when she was going through the divorce with my dad but that was many years ago. TBH, there has never been much she can do for them, except ride it out, and try not to have too much stress in her life.

I'm sorry I can't help beyond that, I hope they can find something to help your DD.