Does vitex help with FHS levels? Can you take it during IVF?

i have taken it the past 2 cycles from CD1 to ovulation. and my cycles are definitely getting shorter, which is what i wanted. but i can't really tell if it is because of the vitex or because my body is naturally adjusting to coming off BCP this summer. so not sure if it is helping but doesn't seem to be hurting.

Anyone ever try vitex and have a positive outcome?