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What Is a Subchorionic Hematoma During Pregnancy?

A subchorionic hematoma — or SCH — is a relatively common problem in early pregnancy that can cause abnormal uterine bleeding. Learn what it is, how it’s typically resolved, and why bleeding during pregnancy warrants an evaluation.

Light vaginal bleeding during early pregnancy is common, affecting up to one in four women in their first trimester. Such bleeding can have many possible causes, including:

  • Embryo implantation  
  • Cervical changes
  • Sexual intercourse
  • Reproductive infection 

A subchorionic hematoma is responsible for about one in 10 cases of abnormal uterine bleeding that occurs between 10 and 20 weeks of gestation. Dr. Christina Parmar and Dr. Rania Ibrahim of New Beginnings OB/GYN offer insight into this relatively common prenatal concern.

What is a subchorionic hematoma?

A subchorionic hematoma (SCH) is the abnormal accumulation of blood inside the uterus during pregnancy. This blood buildup forms between the uterine wall and the outer sac (chorionic membrane) that surrounds your baby within the womb.

Also known as subchorionic hemorrhaging or bleeding, SCH is most common in women who are between 10-20 weeks pregnant or in the later part of their first trimester through about the middle of their second trimester.

Causes

The chorionic membrane is the outermost layer of the “amniotic bubble” that holds your baby. Normally, this membrane is attached to the uterine wall; a SCH occurs when there’s a partial or full separation between this membrane and the uterus. 

Experts don’t know exactly why the chorionic membrane becomes partially or fully detached in some pregnancies. Still, the resulting space within the womb allows blood to pool between your baby’s amniotic sac and the uterus.

Symptoms

This can result in the formation of blood clots (hematomas), which may eventually exit the uterus as vaginal bleeding. The most common SCH symptom is abnormal bleeding; this bleeding can be light and spotty or heavy with the passage of small or large clots. 

Subchorionic bleeding can also be accompanied by pelvic achiness that comes on suddenly and persists, but this is less common. Sometimes, a SCH doesn’t cause vaginal bleeding or any other symptoms and is only discovered during a routine prenatal ultrasound exam.  

Does a SCH threaten my pregnancy?

Subchorionic bleeding rarely causes serious pregnancy or health complications. Most SCHs shrink and heal on their own without treatment, and affected women typically go on to have healthy babies. 

Studies show that in certain cases — such as when factors like a very large SCH or advanced maternal age are present — subchorionic bleeding may increase the risk of serious pregnancy complications like:

  • Heavy bleeding
  • Preterm delivery
  • Pregnancy loss

SCHs are also associated with a fivefold or greater increased risk of placental abruption, a severe, emergency pregnancy complication that occurs when the placenta detaches from the uterine lining.

When does a SCH require treatment?

As concerning as these potential complications are, it’s important to remember that most SCHs aren’t harmful and resolve on their own without treatment or incident. 

However, it’s still important to visit your prenatal care team anytime you experience vaginal bleeding while pregnant. If you have a SCH, your obstetrician will use ultrasound imaging to evaluate your hematoma and determine if treatment is necessary based on factors like:

  • SCH size and location
  • Gestational age (how far along you are)
  • Maternal age and health history
  • Concerning symptoms (i.e., heavy bleeding, cramping)

Treatment for a SCH may involve:

  • Avoiding sex and heavy lifting.
  • Reduced activity or complete bed rest.
  • Monitoring for symptoms that might indicate early labor.
  • A tighter schedule of follow-up ultrasounds. 

The bottom line? A SCH usually doesn’t affect maternal or fetal health, and most babies are born without complications. To learn more, schedule a visit at New Beginnings OB/GYN in Shenandoah, Texas, online or over the phone today.