Q: What is a subchorionic hematoma (or subchorionic bleeding)?
A: A subchorionic hematoma (also known as subchorionic bleeding) is a space of fluid collection, presumably blood, between the gestational sac, usually the placenta, and the uterine wall.
A subchorionic hematoma is a diagnosis made on ultrasound during pregnancy and is usually found either when a sonogram is done for vaginal bleeding in pregnancy or during a routine ultrasound examination. Small subchorionic hematomas in early pregnancy may not be significant, and most women with this finding will go on and deliver a healthy baby.
Larger hematomas are more likely to be detected later in pregnancy, and may be associated with a poorer outcome, such as late abortion or preterm delivery. The reason for a subchorionic hematoma is usually unclear. It has been shown not only in patients with threatened abortion, but also in patients with bleeding disorders, patients with the presence of auto-antibodies, as well as patients receiving anti- coagulants, or those after a severe trauma.
When a subchorionic hematoma is found on ultrasound, women are often told to stay on bed rest. But no study has shown reliably that bed rest will change the outcome in pregnancies with subchorionic hematoma.