Chorionic hematoma is the pooling of blood between the chorion, a membrane surrounding the embryo, and the uterine wall. It occurs in about 3.1% of all pregnancies, it is the most common sonographic abnormality and the most common cause of first trimester bleeding.

Can a subchorionic hematoma cause a miscarriage?

Ultrasonographically detected subchorionic hematoma increases the risk of miscarriage in patients with vaginal bleeding and threatened abortion during the first 20 weeks of gestation. However, it does not affect the pregnancy outcome measures of ongoing pregnancies.

Is a subchorionic hematoma considered high risk?

Small and moderate hematomas often go away on their own. Larger hematomas are more likely to cause problems. There is a higher risk if the subchorionic hematoma is detected in the first 20 weeks of your pregnancy. You should seek treatment as soon as possible for the best possible outcome.