Hematoma..

Hey ladies, ive been for my scan today 8+1 everything was fine with baby. But she said i have hematoma.. is that something to worry about or will it go away on its own? Underneath the baby on the scan. The grey area is the hematoma she told me. Ive read mixed on it.. so not sure never had it before this is my 4th.. & only had my last baby 7 months ago.. could that be the reason?