I was diagnosed w/ endometrial hyperplasia and given provera (medroxyprogesterone). what is it?

A progesterone: Endometrial hyperplasia is basically an overgrowth of endometrial cells (cells lining the uterus), typically due 2 relative excess of estrogen affecting the uterus, compared to Progesterone effect. Some types of hyperplasia can become cancer if untreated. Progesterone applied systemically (by mouth, or by injection) or locally (progesterone iud) can counteract the estrogen & reverse hyperplasia.

Progesterone : Hyperplasia is overgrowth of (most commonly) proliferative phase endometrial glands. Provera (medroxyprogesterone) is a Progesterone agent which promotes maturation of the endometrium from proliferative (or hyperplasia in this case) to secretory phase which then is shed (menses). In most cases Provera (medroxyprogesterone) is effective in treating hyperplasia and can prevent progression to atypical hyperplasia or cancer.