I think it could be a peri sac haemetoma? If so then it could be the cause of the bleed. I think it is like a little sac of blood but it doesn't generally cause any issues with the baby
This is what I have read as well, and that even jsut a sneeze or a cough can cause the leaking of blood, and it is often bright red, which is horribly scary when pregnant. Hopefully you can see your oB or Dr soon and get another scan down the track a little and they can monitor its size, but it was good to read that is can resolve itself. It can be very amazing what the body can reabsorb. I still had a pretty large amount of bleeding and clotting that we expected to come out, but in the end it all liquified and was reabsorbed.