Ok... I usually don't have too many "girly parts" related questions. I pretty well know the female reproductive system as well as I know my own name. However, I can't find what I'm looking for on this one. I know what signals the body to start AF... I know what signals the body to O... I know what is supposed to happen after O thru the next AF or ! But, when the shows up... What exactly makes her pack up and go home? I'd like about a gallon of whatever it is right now... LOL But, it's a serious question that driving me mad! I've looked at the hormone patterns throughout an entire menstrual cycle, and I don't see ONE PARTICULAR thing that screams, "Hey, , GO AWAY!" Help?