Small perigestational/subchorionic hemorrhage?

sa

I'm 6 weeks I went to the er with terrible cramping and back pain. I was told there was a small sack no heart beat yet which is normal at 5 weeks 6 days but on my report they put I have a Small perigestational/subchorionic hemorrhage I'm just so curious as to why this wasn't brought to my attention. All my bleeding has been brown blood but still