IVF VS Letrozal and IUI

Ma

I need some advice! we've had six cycles of Letrozal and one cycle of clomid all fail. we have the option to do Letrozal and Gonal-F with an IUI, but the doctor says I would have a high chance of switching to IVF in the middle of the cycle because of my ridiculously high AMH. I was wondering if anyone ever had this happen to them or just someone else's opinion on the situation.