I passed a large sac of tissue this morning, it was stuck to the top of my tampon. It is about the size of a half dollar and about a quarter inch thick. I had a tubal ligation by cauterization July of 2011. I have never had anything like this pass before, other than normal lining. I would like to send a picture of it. My husband thinks it's a placenta, I'm kind of leaning toward that, but of course I am hoping he is wrong.