I'm trying to remember in which particular one of my books I read this!

Just because you have painful, heavy and clotty periods it does not necessarily indicate that you have PCOS nor anything else wrong - it could just be normal for the way your body works.

Eostrogen withdrawal just refers to a drop in eostrogen levels, normally it is a drop in the levels of progesterone that results in AF.

If your cycle is regular then chances are good that you are ovulating around the same time each cycle. While cycles may be different lengths, the one thing that is generally consistent is the length of the luteal phase. If cycles are going to vary in length, then it will be the follicular phase (when ovarian follicles are developin in order to release an egg) that varies, and the luteal phase (time between ovulation and AF) will be consistent from cycle to cycle.

Sorry for the confusion. I'll have a search around and see if I can find the passage I'm thinking of... there's one of three or four books it could be, so it may take a while!

BW