What is Subchorionic Hemorrhage?
This condition is also referred to as subchorionic hematoma. There is excessive bleeding and a collection of blood or hematoma that forms between the chorionic membrane surrounding the embryo, and the wall of the uterus. Subchorionic hemorrhage is caused because the membrane surrounding the embryo separates from the inner lining of the uterus. It is the most common cause of bleeding in the first trimester.
How Does a Subchorionic Hemorrhage Affect My Baby?
There are a number of factors that determine how this condition affects the baby including how large the hematoma is, the mother’s age and how far along the fetus is in its development. Older pregnant women with large amounts of bleeding have higher rates for miscarriage. Women who experience subchorionic hemorrhage in late first trimester or in second trimester also have an increased chance for miscarriage. Subchorionic hemorrhage also increase the risk for stillbirth, separation of the placenta from the uterus after 20 weeks of pregnancy and contractions opening the cervix before 37 weeks of pregnancy known as preterm labor.
How is the Size of a Hematoma Determined?
A subchorionic hematoma is classified as small if it is less than 20 percent of the size of the gestational sac, which is the structure that holds the embryo and the amniotic fluid. It is classified as medium sized if it 20 to 50 percent of the size of the gestational sac, and large if it is more than 50 percent of the size of the gestational sac.
Does the Size of the Hematoma Determine Its Outcome?
Yes. A hematoma that is small or moderate in size often subsides within one to two weeks. However, a large hematoma that has caused 30 to 40 percent of the sac surrounding the embryo to separate from the wall of the uterus may continue to get larger, causing the gestational sac to become compressed and membranes to burst, which will ultimately abort the pregnancy.
How is the Presence of a Subchorionic Hemorrhage Determined?
Ultrasound is the most commonly used method for determining the presence of a subchorionic hemorrhage because it can be easily performed at the patient’s bedside and because there is no risk from radiation as with an MRI or CT scan. However, ultrasound uncovers about 20 percent of all subchorionic hemorrhages, especially if the blood doesn’t gather in the space between the chorionic membrane and the wall of the uterus. An ultrasound is most effective in finding a subchorionic hemorrhage if it is performed immediately after there has been an episode of vaginal bleeding. Using a Color Doppler also increases the ability to find a subchorionic hemorrhage.
[Featured Image Courtesy of gerbsrandomthoughts]