Subchorionic Bleeding in Pregnancy: What to Know

A subchorionic haematoma is a small collection of blood between the pregnancy sac and the wall of your womb. It is a common finding on early scans and a frequent cause of bleeding in the first trimester. While the word sounds frightening, most subchorionic bleeds resolve on their own without affecting the pregnancy. This guide explains what they are, how they behave, and what to expect.

How Subchorionic Haematomas Form

No one knows exactly why they form, but it is thought to happen when a small blood vessel in the lining of the womb ruptures as the embryo implants. The blood pools between the chorionic membrane (the outermost layer surrounding the embryo) and the uterine wall. Your body either reabsorbs it gradually or you bleed it out as dark brown or red spotting. Many women only discover they have one during a routine early scan — the haematoma shows up as a crescent-shaped dark area near the gestational sac.

Subchorionic haematomas are more commonly identified now than in previous decades, largely because early ultrasound scanning has become routine. They are not thought to be caused by anything the mother does or does not do.

What a Subchorionic Haematoma Feels Like

Some women experience no symptoms at all and discover the haematoma only on a scan. Others notice:

Brown spotting or discharge — this is old blood being slowly expelled; it is less alarming than it looks
Light to moderate red bleeding — fresh blood being passed; this warrants contact with your early pregnancy unit (EPU)
Mild cramping — the womb contracting slightly as it expels blood

Brown spotting without pain after an early scan showing a small haematoma is generally a reassuring pattern — it usually means the body is clearing the blood. Bright red bleeding, especially in larger amounts or accompanied by significant pain, should always be assessed promptly.

What Happens Next

Most subchorionic haematomas are small and resolve within a few weeks. Your midwife or early pregnancy unit may arrange a follow-up scan to confirm it has shrunk or disappeared. The scan also allows the team to check that the pregnancy itself is progressing well alongside the haematoma.

The outlook depends largely on the size and location of the haematoma:

Small haematomas (those covering a small percentage of the pregnancy sac) almost always resolve without complication. The blood is simply reabsorbed by the body or passed as spotting.
Larger haematomas are monitored more closely. They can occasionally be associated with an increased risk of complications such as further bleeding, and may take longer to resolve.
Retroplacental haematomas (those located behind the placenta rather than at the edge) tend to attract closer monitoring, as their position means they can potentially affect the blood supply to the placenta.

If your bleed increases, turns bright red, or you develop significant pain, contact your early pregnancy unit or call 111 for advice. If bleeding is very heavy — soaking a pad — or you feel faint or have severe one-sided pain, call 999 or go to A&E.

Activity and Rest

Bed rest is not proven to help subchorionic haematomas resolve, and it is not routinely recommended by UK midwives. Most women are advised to:

Avoid strenuous exercise, heavy lifting, and high-impact activity until the haematoma has settled or resolved
Abstain from penetrative intercourse until the bleeding has stopped and a follow-up scan has confirmed things are settling
Continue with gentle day-to-day activity unless your midwife advises otherwise

Try to rest if you feel anxious or physically uncomfortable, but do not feel that you must stay in bed — the evidence does not support this as a treatment.

Frequently Asked Questions

### Does a subchorionic haematoma mean miscarriage?

Not usually. Most small haematomas resolve without affecting the pregnancy. The presence of a haematoma does not mean miscarriage is inevitable or even likely. Your scan will confirm the size and location, and your team will advise on the level of monitoring needed. Many women with subchorionic haematomas go on to have uncomplicated pregnancies.

Will I need bed rest?

Bed rest is not proven to help and is not standard NHS advice. Most midwives advise avoiding strenuous activity and intercourse until the bleed has settled, but you do not need to confine yourself to bed. If you are unsure what level of activity is appropriate for your situation, ask your midwife or EPU team directly.

How is a subchorionic haematoma treated?

There is no specific medical treatment to make a haematoma disappear faster. Your body reabsorbs the blood or expels it as spotting. The focus of care is monitoring — follow-up scans to check the haematoma is shrinking and that the pregnancy is continuing well. Progesterone supplements are sometimes discussed but are not proven to affect haematoma outcomes; speak to your doctor if this is raised.

Further reading:

NHS — Common pregnancy symptoms

Always contact your midwife, GP, or early pregnancy unit if you are concerned about bleeding or pain during pregnancy. In an emergency, call 999.