Natural cycle IVF questions

Micro

Those who did a natural cycle with a high FSH over 40, how was your protocol structured?

Did you take Estrace/BCPs to lower your FSH to a certain number?

Did you take Clomid/letrozole?

And how did you keep your FSH from getting too high? I know high FSH keeps the follicles from growing, so how can a natural cycle in keeping FSH low enough to grow follicles? Thanks.