In some pregnant women, blood clots can form inside the layers of the placenta, leading to what is called a subchorionic hematoma--technically it is blood accumulated inside the folds of the chorion. If the clot becomes large enough, it can cause separation of the placenta and the uterine wall. However, most subchorionic hematomas heal themselves without any treatment by 20 weeks gestation. There are signs and symptoms of subchorionic hematoma you can watch for during the early weeks of pregnancy.
The main symptom of subchorionic hematoma is vaginal bleeding. Bleeding can be heavy or light, depending on the size of the subchorionic hematoma. Bleeding can also be a sign of miscarriage during early pregnancy, so you should call your doctor any time you notice vaginal bleeding during the course of your pregnancy. If a subchorionic hematoma is small enough, it may never cause bleeding or spotting and will eventually resolve on its own.
What to Expect Online reports that one in five women can experience bleeding in early pregnancy, however it's not known how much of this is due to subchorionic hematoma. Pregnancy loss as a result of subchorionic hematoma is one to three percent. In fact, more than 50 percent of women who experience first trimester bleeding, whether its related to subchorionic hematoma or something else, will go on to have a healthy pregnancy, according to What to Expect Online.
Making the Diagnosis
A high-tech ultrasound scan can confirm a diagnosis of subchorionic hematoma. Doctors may use an abdominal ultrasound on the belly or a transvaginal ultrasound through the vagina to make the diagnosis. Sometimes, the subchorionic hematoma is difficult to spot. However, if bleeding is present and doctors can assess the well-being of the fetus through ultrasound, the doctor makes the diagnosis of subchorionic hematoma. In many cases, doctors diagnose subchorionic hematoma during a routine ultrasound when the patient notices no symptoms.
There's no known cause of a subchorionic hematoma, but it could relate to the implantation of the egg. It's possible the egg tears away or slightly separates from the uterus at the time of implantation, causing bleeding. There are no ways to prevent subchorionic hematoma, and it occurs among women of every age and race.
Just as there is no cause of subchorionic hematoma, there is also no specific treatment. Some doctors encourage women to take it easy, and it's possible a doctor will advise women with subchorionic hematoma to refrain from sexual activity until the clot bleeds out or dissolves. If the doctor feels it's necessary, she may use blood thinners to essentially make the clot "bleed out." Hormones estrogen and progesterone may also be prescribed to help the early development of pregnancy, if necessary.