Anyone heard of an AV fistula after C-section?

Ro

I had an ultrasound the other day because I had uncontrollable bleeding way after the 8 week PP mark and they said I'm developing a possible AV fistula on my c-section scar. Has anyone heard of this or has anyone had this that can give me a little more info on it? I'm not exactly sure what it is and if it's serious or not. I have to go get an MRI in 3 months to get more answers....