How Did Menopur & Ovidrel Restore My Cycles?

I have been anovulatory for around 7 years after starting nexplanon. After removal in Jan 2024, my cycles never returned. In Jan 2025 I tried lamotrigine and nothing happened.

Since then, I’ve done 3 medicated cycles (failed) and in May during a break we saw that my ovaries began recruiting their own follicles for the first time.

I have read quite a bit/understand about how menopur and ovidrel work, but I can’t find anything about how anyone had it “kick start” their own cycles again after being without one for so long. How did this happen?