ConditionWomen's & pregnancy health
Subchorionic Hematoma (Subchorionic Bleed)
A subchorionic hematoma is a collection of blood between the outer membrane around the pregnancy (the chorion) and the wall of the uterus. It is one of the most common findings on ultrasound when there is bleeding in the first trimester. Many cause spotting or bleeding, and most are reabsorbed by the body by mid-pregnancy with no harm to the baby. Large hematomas carry a somewhat higher risk of miscarriage and later complications, so they are monitored with follow-up scans.
Also called: Subchorionic hemorrhage, subchorionic bleed, perigestational hemorrhage, SCH
At a glance
- What it is
- A pool of blood between the gestational sac membranes and the uterine wall.
- How common
- Seen in a meaningful minority of first-trimester ultrasounds done for bleeding; also found without symptoms.
- Symptoms
- None, or spotting to heavy bleeding, often brown or red; sometimes mild cramping.
- Diagnosis
- Transvaginal or abdominal ultrasound.
- Treatment
- No specific treatment; monitoring with scans. Most resolve by 20 weeks.
When to get help
Call 911 or go to the ER
- Heavy bleeding soaking a pad every hour for 2 hours, or passing large clots
- Bleeding with dizziness, fainting, a racing heart or pale clammy skin
- Severe one-sided pain or shoulder-tip pain in early pregnancy before an ultrasound has confirmed the pregnancy is in the uterus (possible ectopic pregnancy)
- In later pregnancy: constant severe belly pain, a hard tender uterus or reduced baby movements with bleeding (possible placental abruption)
See a doctor within a day or two
- Any new vaginal bleeding in pregnancy: contact your obstetric provider or early pregnancy unit the same day
- Bleeding with fever, chills or foul-smelling discharge
- Bleeding in someone with Rh-negative blood type (may need an anti-D injection)
- Fluid leaking from the vagina
Book a routine appointment
- Light brown spotting with a known small hematoma that is stable on scan, to report at your next visit
Usually safe to manage at home
- A known small hematoma with light spotting: rest when needed, use pads not tampons, and keep track of bleeding
What is a subchorionic hematoma?
In early pregnancy, the chorion is the outer membrane of the gestational sac. It attaches to the uterine lining, where the placenta forms. If part of this attachment separates slightly, blood vessels bleed into the gap and a hematoma (blood collection) forms. The blood may stay trapped or drain through the cervix as spotting or bleeding.
It is closely related to placental abruption, which is a separation of the placenta from the uterine wall. A subchorionic hematoma is usually early, small and away from the placental center, while placental abruption typically happens later in pregnancy and is more dangerous.
Symptoms
- No symptoms: many are found by chance on a routine scan
- Spotting or bleeding in pregnancy, from light pink or brown to bright red, sometimes heavy
- Brown discharge as old blood drains
- Mild cramping or pelvic discomfort
Bleeding can stop and start over several weeks.
Causes and risk factors
The exact cause is usually unknown. It may relate to how the placenta implants. Factors associated with a higher chance include:
- IVF and other assisted reproduction
- Previous miscarriages
- Uterine abnormalities or fibroids
- Clotting disorders or blood thinners
- High blood pressure
- Injury to the abdomen
Sex, exercise and normal daily activity do not cause a subchorionic hematoma.
Diagnosis
An ultrasound, usually transvaginal in early pregnancy, shows a crescent or wedge-shaped dark area next to the gestational sac. The scan also confirms:
- The pregnancy is inside the uterus (ruling out ectopic pregnancy)
- Whether there is a heartbeat
- The size of the hematoma, often described in centimeters, milliliters or as a fraction of the gestational sac
Doctors also check your blood type. If you are Rh-negative, you may need an anti-D immunoglobulin injection after bleeding to protect future pregnancies.
Size and miscarriage risk
| Size relative to the gestational sac | General significance |
|---|---|
| Small (under about a quarter of the sac) | Usually resolves; little added risk |
| Moderate | Monitored; modestly higher risk |
| Large (half the sac or more) | Higher risk of miscarriage and later complications |
Research findings vary, but on average, women with a subchorionic hematoma and bleeding have a somewhat higher risk of miscarriage than those without one. The risk is greater with large hematomas, bleeding earlier in pregnancy (before 8 weeks) and in women over 35. Seeing a normal heartbeat is reassuring: once a heartbeat is confirmed, most pregnancies continue. Bleeding with a normal heartbeat is often called a threatened miscarriage.
Studies also link subchorionic hematoma to a slightly higher chance of later complications, including placental abruption, preterm labor, early rupture of membranes and growth restriction. Your provider may arrange extra scans later in pregnancy.
Treatment and care
There is no medicine or procedure that removes a subchorionic hematoma. The body usually reabsorbs it over weeks. Care involves:
- Follow-up ultrasounds to check the hematoma is shrinking and the baby is growing
- Anti-D immunoglobulin if you are Rh-negative and bleeding
- Progesterone is sometimes prescribed for threatened miscarriage, mainly for women with previous miscarriages, though evidence specific to hematomas is limited
- Reviewing blood thinners with your doctor if you take them
What to avoid with a subchorionic hematoma
Strict bed rest has not been shown to help and increases the risk of blood clots. Advice varies between providers, but commonly includes:
- Avoiding heavy lifting and very strenuous exercise while bleeding
- Avoiding sex or anything in the vagina while actively bleeding, if your provider recommends it
- Using pads rather than tampons
- Avoiding aspirin and NSAIDs unless prescribed
- Staying hydrated and keeping normal light activity
Outlook
Most subchorionic hematomas resolve by the end of the first trimester or by around 20 weeks, and most pregnancies continue to a healthy birth. Larger hematomas need closer follow-up but still often end well.
Frequently asked questions
Is a subchorionic hematoma dangerous?
Most are not. Small hematomas usually disappear on their own and do not affect the baby. Large ones carry a higher risk of miscarriage and later complications such as placental abruption and preterm birth, so they are monitored with ultrasound. Heavy bleeding, pain or dizziness need urgent care.
How long does a subchorionic hematoma last?
Most are reabsorbed within a few weeks and are usually gone by 20 weeks of pregnancy. Brown spotting may continue for a while as old blood drains. Your provider will usually repeat the ultrasound in 1 to 3 weeks to check that it is getting smaller.
Can a subchorionic hematoma cause miscarriage?
It can increase the risk, especially if the hematoma is large, bleeding starts before 8 weeks, or the mother is over 35. However, most pregnancies with a subchorionic hematoma continue normally, particularly once a healthy heartbeat is seen and the hematoma shrinks.
What should I avoid with a subchorionic hematoma?
Common advice is to avoid heavy lifting, intense exercise, and sex while you are actively bleeding, and to use pads instead of tampons. Avoid aspirin and NSAIDs unless prescribed. Strict bed rest is not recommended because it does not prevent miscarriage and raises the risk of blood clots.
Is bleeding from a subchorionic hematoma the baby's blood?
No. The blood comes from the mother's blood vessels in the uterine lining, not from the baby. Bleeding does not mean the baby is losing blood. That is why many pregnancies with bleeding from a hematoma continue normally when the baby's heartbeat and growth are fine.
Sources
This guide was written from current patient and clinical guidance, including:
- American College of Obstetricians and Gynecologists (ACOG): Bleeding During Pregnancy FAQ
- American College of Obstetricians and Gynecologists: Practice Bulletin No. 200: Early Pregnancy Loss
- Cleveland Clinic: Subchorionic Hemorrhage
- Society of Radiologists in Ultrasound: Diagnostic Criteria for Nonviable Pregnancy Early in the First Trimester
- NHS: Vaginal bleeding in pregnancy