Subchorionic Hemorrhage Causes: What to Know When Pregnant & Experiencing Menstrual Bleeding or Subchorinoic Hemorrhage

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A subchorionic hemorrhage is caused when blood collects between the chorionic membrane (a membrane that develops around a fertilized egg) and the wall of the uterus. If blood leaks through the cervix, this subchorionic bleeding may result in vaginal bleeding. However, not all bleeding occurs due to subchorionic hemorrhage.

For women who are pregnant, vaginal bleeding is a fairly common occurrence, and one that is not usually dangerous. It can, of course, be very distressing – but around 25% of women experience some form of it during their first trimester of pregnancy, so this isn’t necessarily anything to worry about. However, subchorionic hemorrhage is potentially a dangerous complication of pregnancy, so vaginal bleeding should never be ignored.

Around 1.3% of pregnant women experience subchorionic bleeding, but only 20% of women who experience any type of vaginal bleeding during their first trimester will develop subchorionic hemorrhage. Because of this risk, it’s important to consult your doctor if you experience any bleeding at all even if it is unlikely that it is dangerous.

Severe subchorionic bleeding can lead to rupture of the subchorionic membrane, and in the worst cases may lead to a miscarriage. Of women who develop subchorionic hemorrhage, around 9% miscarry. The risk increases somewhat in women over 35.

Symptoms and Diagnosis

The most obvious symptom is vaginal bleeding. For this reason, any vaginal bleeding should be checked out by your doctor as soon as possible. Women with subchorionic bleeding may also experience moderate or severe abdominal pain.

Diagnosis is usually made on the basis of symptoms, and the results of an ultrasound to determine the size and location of the subchorionic bleeding. However, ultrasound is not always reliable in diagnosis.

Subchorionic Hemorrhage Treatment

Since there is no other treatment for subchorionic hemorrhage, women who develop subchorionic bleeding are usually prescribed complete bed rest until bleeding stops. A woman who is experiencing subchorionic bleeding will typically undergo several ultrasounds over the course of the first trimester (and perhaps into the second if bleeding continues) to monitor the health of the fetus.


Chen, P., Sickler, K., Maklad, N. Acute obstetric and gynecological emergency. Emergency Radiology. 5:5 1998. Springer Berlin/Heidelberg.

eMedicine: Subchorionic Hemorrhage