A subchorionic hematoma is a gathering of blood between the outer wall of the placenta and the inner wall of the womb ( uterus). The placenta is the organ which connects the fetus to the wall of the uterus. The placenta performs the feeding, breathing (oxygen to the fetus), and removes the waste ( excretory work) of the fetus.
SCH is the most common abnormality found on an ultrasound done during the first trimester or early second trimester of pregnancy. If there has been little or no vaginal bleeding, early small hematomas usually shrink on their own and do not affect the baby or pregnancy. The blood is gradually absorbed over about 1-2 weeks. When bleeding starts later in pregnancy, is larger or occurs in an older patient, the outcome may not be as good. Larger hematomas may get bigger, which increases the chances for miscarriage. SCH also increases the risk of premature detachment of the placenta from the uterus, preterm ( premature) labor and stillbirth.
There is no known cause for SCH. However, it may occur at the time when the fertilized egg implants on the uterus and slightly separates from the uterus.
Most patients with a small subchorionic hematoma in first trimester have no problems. If problems do show up, they may include:
An ultrasound will likely be performed.