small subchorionic hemorrhage?

What Causes a Subchorionic Hematoma? The specific causes of subchorionic hematoma aren't clear. There are some risk factors associated with them, including:  Malformation of the uterus History of recurrent miscarriages History of pelvic infections Trauma Early-onset preeclampsia, which is a serious pregnancy complication marked by high blood pressure and organ failure Severe high blood pressure In vitro fertilization