Saw my gyn today. She's totally knowledgable about cups and thinks they're great. Her opinion of the controversy of endometriosis/backflow (?) of menstrual fluid back into the uterus and beyond is that it's not an issue as it takes a lot of pressure to push anything back thru cervix into uterus. I also found out that even tho I thought I was losing a lot of blood per cycle (average 180 ml), there is nothing medically wrong with me in that area. So, yay! Now I know and I can quit keeping track of how much blood I lose ea. cycle and just enjoy my cup! Just had to share.