I know this sounds gross ... But if you pass any type of tissue, you should retrieve it, put it in a sealed container and take it to your doctor as soon as possible so they can perform lab work on it and see what it is exactly.

All you passed was this grayish colored tissue? No bleeding or anything? I would have assumed a miscarriage but that's usually accompanied by bleeding and cramping. Well, not always ... But that's what I experienced when I had a miscarriage. I wish I could give you a better answer ... Good luck!

I had a miscarriage before and I have bine haveing some pain......

You should probably get yourself in to see the dr as soon as possible. If you pass any other pieces of tissue, make sure you take them along with you. Good luck!