if you look back to the original data on POP's (and ECP that are progesterone based) you'll see that the mice/rats used had changes in their uterine lining after being given the medication that could prevent implantation via electron microscopy. As far as it not being approved in the US, tech HBC is an abortifacient so i am not too worried about it not being approved just b/c of that. In the case of mifepristone - it works by a different methodology than any of these other things we are talking about, so IMHO a totally different line of thinking/discussion.