Subchorionic haematoma: what it is and what usually happens

What it is

A subchorionic haematoma is a collection of blood between the wall of the uterus and the chorion — the membrane around the pregnancy sac. It happens when a small area separates slightly and bleeds.

It is usually found on an early scan, either because there has been spotting or incidentally while looking at something else. Many women with one have no bleeding at all.

The scan report will describe its size relative to the sac, which is the main thing your doctor is watching.

What usually happens

Most small haematomas reabsorb over weeks, and the pregnancy continues normally. Bleeding, if it occurs, is often brown as old blood drains, and may come and go for a while.

Larger ones, and those found later in the first trimester, carry a somewhat higher risk of miscarriage and of complications later in pregnancy — which is why they are monitored with repeat scans rather than ignored.

There is no treatment that makes a haematoma resolve faster. Progesterone is sometimes prescribed in specific situations; bed rest has not been shown to help and is not routinely advised.

Ask your doctor for the practical version: what size is it, what is the plan for rescanning, what restrictions apply, and what should bring me in.

What to do meanwhile

Follow the specific advice you are given. Commonly: avoid sex until it has resolved, avoid heavy lifting and strenuous exercise, and rest when you are bleeding — while remembering that ordinary activity did not cause it.

Use pads rather than tampons, and note the pattern of bleeding so you can describe it.

Rh-negative women need an anti-D injection after significant bleeding — make sure your blood group is known and mention it every time.

And manage the anxiety honestly: this is a diagnosis that produces weeks of waiting. Ask for the rescan date rather than reading forums, and tell your doctor if the worry is affecting you.

When to see a doctor

Go to hospital immediately at any stage for: heavy bleeding, severe or constant abdominal pain, a gush or steady trickle of fluid, severe headache with visual changes, sudden swelling of the face and hands, high fever, fainting, or reduced fetal movements after 28 weeks. Call 108 if you cannot travel quickly.

Same-day with a known haematoma: bleeding that becomes heavy or bright red, passing clots, cramping or contractions, fever, or foul-smelling discharge. And keep every scan appointment even if the bleeding has stopped.

This article is general information, not medical advice, and is no substitute for personal medical advice. For any decision about your or your child's health, please consult your doctor.

Frequently asked questions

Q: Did I cause it by lifting something? — No. Subchorionic haematomas are not caused by ordinary activity, exercise or travel.

Q: How long does it take to go? — Often a few weeks; sometimes longer. Repeat scans track it, and many are gone by the second trimester.

Q: Does it mean I will miscarry? — Most pregnancies with a small haematoma continue normally. Larger ones carry more risk, which is what the monitoring is for.

Q: Should I stop working? — Usually not, unless your doctor advises it or your job involves heavy physical work. Ask about your specific case rather than assuming.