Subchorionic Haematoma: Complete Guide
Seeing the words "subchorionic haematoma" on a scan report can be alarming, especially if you weren't expecting it. It's actually a fairly common finding in early pregnancy, and the vast majority resolve without causing harm. Here's what it means, why it happens, and what to watch for.
What a subchorionic haematoma is
A subchorionic haematoma (sometimes spelled "hematoma") is a small pool of blood that collects between the wall of the uterus and the chorionic membrane — the outer membrane surrounding the developing pregnancy sac. It's essentially a localised bleed that hasn't found its way out, and it's usually spotted on an ultrasound scan, either because you've had bleeding and were sent for a check, or incidentally during a routine scan.
Why it happens and how common it is
The exact cause isn't always clear, but it's thought to happen when small blood vessels at the edge of the placenta or membrane separate slightly from the uterine wall. It's one of the more common findings in early pregnancy scans, particularly in women who report some vaginal bleeding or spotting in the first trimester.
Symptoms to expect
- Vaginal bleeding or spotting, which can range from light brown discharge to brighter red blood
- Bleeding is usually painless, though some women notice mild cramping
- Some subchorionic haematomas cause no symptoms at all and are only found on a scan
How it's managed
- Diagnosis is made by ultrasound, which shows the size and location of the haematoma.
- Most small and medium haematomas resolve on their own as the body reabsorbs the blood over time, with no specific treatment needed.
- Follow-up scans are usually arranged to check the haematoma is shrinking and the pregnancy is developing normally.
- Practical advice often includes resting when you can and avoiding heavy lifting or strenuous exercise until it has resolved, though this varies by individual case.
- Larger haematomas are monitored more closely, as they are associated with a somewhat higher risk of complications such as miscarriage or, later in pregnancy, preterm birth — though many still result in a healthy ongoing pregnancy.
When to contact your midwife or EPU
Contact your midwife, GP, or early pregnancy unit if you notice:
- Bleeding that becomes heavier rather than lighter
- Passing clots or tissue
- Significant abdominal pain
- Feeling faint, dizzy, or unwell
Frequently Asked Questions
Is a subchorionic haematoma dangerous?
Most subchorionic haematomas are small, cause no lasting problems, and resolve on their own within a few weeks. Larger ones carry a somewhat higher risk of complications and are monitored more closely with follow-up scans, but the majority of women with this finding go on to have healthy pregnancies.
Will a subchorionic haematoma harm my baby?
In most cases, no — the haematoma is located outside the amniotic sac and away from the baby directly, and it typically reabsorbs without affecting development. Your midwife or sonographer will monitor its size and your pregnancy's progress with follow-up scans to make sure everything continues as expected.
How long does a subchorionic haematoma take to go away?
This varies considerably from a couple of weeks to a couple of months, depending on its size. Bleeding may continue on and off while it resolves, which can be unsettling but doesn't necessarily mean things are getting worse. Follow-up scans are the best way to track whether it's shrinking as expected.
This article is for informational purposes only and does not constitute medical advice.
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