Subchorionic Hematoma

A subchorionic hematoma happens when blood forms between the wall of your uterus and the chorionic membrane during pregnancy. The chorionic membrane is the outermost layer of the pregnancy sac. The amniotic sac, or the bag of waters, is where the fetus develops. It has two layers: the chorion and the amnion.

This condition can be associated with vaginal bleeding (subchorionic hemorrhage). It’s the most common finding associated with vaginal bleeding during 10 to 20 weeks of pregnancy. But some women have no symptoms.

Some hematomas may increase the risk of certain pregnancy complications. But many go away without treatment and don’t cause issues. Your healthcare provider will recommend a plan for follow-up after assessing the hematoma.

Symptoms of subchorionic hematoma

The most common symptom of a subchorionic hematoma (hemorrhage) is vaginal bleeding in the first half of pregnancy. The bleeding may:

• Be heavy with clotting
• Be light spotting
• Happen alongside pelvic cramping (rare)

The majority of people have no bleeding at all. They learn about the hematoma during a routine ultrasound.

Contact your provider immediately if you have any bleeding during pregnancy. Finding the cause of it as early as possible is key.

Subchorionic hematoma causes

A subchorionic hematoma happens when the chorion membrane detaches from the wall of your uterus. This detachment from the uterine wall can be small or large.

Healthcare providers aren’t entirely sure what causes this separation to occur. But certain conditions may put you at a higher risk of developing a subchorionic hematoma, including:

• Autoimmune conditions, especially antiphospholipid syndrome
• Blood clotting disorders
• High blood pressure
• History of pelvic infections
• IVF pregnancy
• Recurrent miscarriages
• Uterine irregularities

Complications of this condition

Subchorionic bleeding may increase your chances of pregnancy complications. Some of the possible complications are:

• Excess vaginal bleeding
• Miscarriage
• Placental abruption

Many subchorionic hematomas don’t cause complications. Your healthcare provider will evaluate your hematoma and determine if treatment is necessary. They base this on several factors, including the size of the hematoma and the stage of pregnancy.

How doctors diagnose this condition

An ultrasound is the main way healthcare providers diagnose a subchorionic hematoma. It looks like a crescent-shaped collection of blood. You’ll have a belly ultrasound or a transvaginal one.

You may get this ultrasound if you have vaginal bleeding. Or your provider may find a hematoma during a routine prenatal ultrasound.

If you have vaginal bleeding, your provider will do other tests or exams to check for complications. For example, they may do a pelvic exam to assess your cervix. They may also check the fetal heart rate.

How is it treated?

Many subchorionic hematomas will heal on their own over time, just as a cut on your skin would. Your healthcare provider will evaluate your symptoms and review your health history. They’ll come up with a treatment plan based on the size and location of the hematoma and the fetus’s gestational age.

Your provider may recommend:

• Reduction in activities, like exercise and lifting heavy objects
• Avoiding sex
• Follow-up ultrasounds to assess its size
• Monitoring symptoms that suggest early labor, like contractions and cramping
• Hospitalization
• Anti-D immune globulin if you have a negative blood type (are RhD-negative)

When should I see my healthcare provider?

If you have a subchorionic hematoma diagnosis, contact your healthcare provider if:

• There are changes in your symptoms
• The amount of bleeding increases
• You have contractions or cramping
• You feel dizzy or lightheaded

How long do subchorionic hematomas last?

There’s no set amount of time for how long it takes a subchorionic hematoma to heal. In some cases, it’ll shrink in size on its own over a few weeks without causing any complications. Other times, the hematoma can be large and require extra medical care. Your healthcare provider may be able to provide more insight.

Is having a subchorionic hematoma considered a high-risk pregnancy?

It depends on how severe the hematoma is and whether you have other medical conditions. If your bleeding is excessive or the hematoma is large, your provider will likely consider your pregnancy high risk. But small hematomas with minimal bleeding rarely pose a problem.