Subchorionic Hematoma: Causes & Diagnosis

A subchorionic hematoma is a collection of blood between the uterine wall and the chorionic membrane during pregnancy. The chorionic membrane is the outer layer that separates the amniotic sac from the uterine wall. The most common symptom is vaginal bleeding. However, some women do not experience any symptoms. Most subchorionic hematomas resolve on their own without causing complications during pregnancy.

How common is a subchorionic hematoma?

Subchorionic hematomas most commonly occur in women who are between 10 and 20 weeks pregnant. They account for about 10% of all cases of vaginal bleeding. Most hematomas are not a cause for concern because they are small or cause only light bleeding.

What are the risk factors for a subchorionic hematoma?

Previous uterine infections;
Previous uterine trauma;
A history of miscarriages;
Pregnancy following assisted reproduction;
High blood pressure.

What are the symptoms of a subchorionic hematoma?

The most common symptom of a subchorionic hematoma is vaginal bleeding during the first half of pregnancy. The bleeding can range from heavy bleeding with clots to light spotting. Sometimes it may be accompanied by cramping in the pelvis or lower abdomen, but pain is usually absent. It is important to note that many women experience no symptoms at all—a subchorionic hematoma is often discovered incidentally during a routine ultrasound examination. In all cases where bleeding occurs during pregnancy, it is recommended to consult an obstetrician-gynecologist to rule out possible

What causes a subchorionic hematoma?

A subchorionic hematoma occurs when the chorionic membrane partially detaches from the uterine wall. The chorion is the outer layer of the amniotic sac, and the amniotic sac itself is the space within the uterus where the baby develops. The separation from the uterine wall can be minor or more extensive. A doctor cannot always determine exactly why this separation occurs. However, it is known that certain conditions and factors can increase the risk of developing a subchorionic hematoma.

What are the complications of a subchorionic hematoma?

Excessive vaginal bleeding;
Miscarriage;
Preterm birth;
Placental abruption;

Most subchorionic hematomas resolve on their own and do not cause pregnancy complications. An obstetrician-gynecologist evaluates the condition and decides on a treatment or monitoring strategy, taking into account several factors, including the size of the hematoma, its location, and the duration of the pregnancy.

How is a subchorionic hematoma treated?

Most subchorionic hematomas resolve on their own over time and do not require specific treatment. An obstetrician-gynecologist will evaluate the patient’s symptoms, take a medical history, and use an ultrasound to determine the location and size of the hematoma. The treatment approach is selected on an individual basis, taking into account these factors and the gestational age of the pregnancy.

Treatment options for subchorionic hematoma:

Limiting physical activity;
A restful regimen;
Temporary avoidance of sexual intercourse;pregnancy complications.
Regular ultrasound examinations to monitor the size and progression of the hematoma;
Monitoring for signs of preterm labor (e.g., uterine contractions, spasms);
Hospitalization if the condition requires more intensive care.

How long does a subchorionic hematoma last?

There is no exact timeframe for when a subchorionic hematoma will completely resolve. In some cases, it gradually shrinks over a few weeks and resolves on its own without causing any complications.

However, in some cases, the hematoma may be larger or persist longer, which can increase the risk of certain pregnancy complications. An obstetrician-gynecologist regularly monitors the course of the hematoma, changes in its size, and its potential resolution based on clinical examination and ultrasound results.

Does a subchorionic hematoma harm my baby?

In most cases, a subchorionic hematoma does not harm the baby. If the hematoma is small, it may not cause any problems or may resolve on its own during pregnancy. A larger hematoma or one that develops later in pregnancy may pose a higher risk of pregnancy complications, so in such cases, the OB-GYN will monitor the pregnancy more closely. It is important to know that in most cases, a subchorionic hematoma does not affect the baby, and the baby is born healthy.

Is a subchorionic hematoma considered a high-risk pregnancy?

This depends on the severity of the hematoma and whether you have any other health conditions. If the bleeding is heavy or the hematoma is large, it is likely that the pregnancy will be considered high-risk. However, if the hematoma is small or causes only minor bleeding, your doctor may suggest a follow-up ultrasound in a few weeks to assess changes in the hematoma.