Prometrium is just progesterone which your body makes normally anyways, except with PCOS some of us dont make as much as we should. I take prometrium when I am preg to get me to stop spotting and the only side effect is the bleeding stops

I really dont know of any bad side effects of taking progesterone b/c like I said its naturally made in our bodies.
I never took it for hyperplasia, but D&C can cause problems for preg if thats a plan later on. Sometimes it can lead to premature labor or incompentant cervix, so if you plan on having kids in the future you should really just take the prometrium. Hope that helps you.