The other day my friend told me she is pregnant, so now I have the urge to tell her I had a miscarriage.
I find that odd you want to tell her you had a miscarriage, is it because the babies have the same father?
No, why would you think that? What a dirty mind you have
I just wanted to know why you would think telling your friend that you had a miscarriage is a good idea, and maybe you had some reason to be concerned about her pregnancy.  Either way, you could really manipulate her emotions by bringing that up. Just be an honest good friend, support her, and you'll be better off.
I'm a bitch and I always want to be on the top.
I understand you want to be above certain people. But toying with people's emotions and bring up a tragic event is not going to help.  And if they find out that you never had a miscarriage, you will most likely lose them as a friend