It's complicated...but is it my place to say anything?

Okay, I'm going to try to make the background info here as brief and non-specific as possible since it's relevant to the situation.
My bff since elementary school (A) and I had a falling out in high school when I started seeing her ex. We never really made up, but have both been able to move on and be civil to one another. We're adults now. I'm married (yes, to the ex) and she is engaged and pregnant. Before this relationship, she was engaged to someone else (B). I got a message from another friend (C) today saying that C's brother and his friends are spreading rumors that A's new fiance (and baby's dad) is married and his wife is also pregnant.
Now, I know we aren't friends anymore, but it kind of ticked me off to hear that. (Grow up, people!) Anyways, my question is this: is it my place to tell her about the rumor? I don't know how far it has spread or any other details. I don't want to stir up any unnecessary trouble/drama for her or myself, but if people were saying such absurd things about my personal life, I would want to know! I also don't want the rumor to get back to her and have her thinking that I was the one who started it.

If you made it, thanks for reading! What's your advice for me??