Subchorionic Hematoma: What Does It Mean for Your Pregnancy?

A subchorionic hematoma (also spelled haematoma) is a collection of blood between the wall of the womb and the chorion, the outer membrane around the developing pregnancy. It is usually found on an ultrasound scan done because of bleeding in early pregnancy, and many settle on their own without treatment.

Cleveland Clinic describes it as the most common finding linked with vaginal bleeding between 10 and 20 weeks of pregnancy. ISUOG, the international society for ultrasound in obstetrics and gynaecology, says it affects about 5% of pregnant women. Some people have no bleeding at all, and the hematoma is noticed by chance on a routine scan.

This guide is for people who have been told about a subchorionic hematoma on a scan. It explains the finding and helps you prepare questions. It cannot tell you what will happen in your own pregnancy.

A known hematoma does not mean new bleeding is safe to watch at home. NHS guidance says to call emergency services (999 in the UK, or your local emergency number) straight away if you are bleeding and have heavy bleeding (such as soaking a pad soon after putting it on), severe tummy pain that stops you focusing on everyday things, pain in the tip of your shoulder, or you feel sick, faint or dizzy, or pass out.

For lighter bleeding or spotting without those signs, contact your maternity unit, or an early pregnancy unit if you are under 20 weeks, on the same day. Follow the specific instructions your own team gave you, as local services differ. Other reasons to call your team include:

• Bleeding that is getting worse, or is still present 14 days after the scan (from one NHS hospital leaflet on subchorionic haematoma).
• New cramping or contractions.
• Feeling dizzy or light-headed.
• Any change in symptoms that worries you.

The main symptom is vaginal bleeding, usually in the first half of pregnancy. It can range from light spotting to heavier bleeding with clots. Pain is usually absent, although some people notice mild cramping.

Bleeding in early pregnancy has several possible causes, including implantation bleeding, changes in the cervix, infection, miscarriage and ectopic pregnancy. Only an assessment, usually with a scan, can show which applies. If free fluid was also mentioned on your scan report, our guide on free fluid in the pelvis explains that wording separately.

An ultrasound scan is the main test. Cleveland Clinic says it can be done over the tummy or with a probe inside the vagina, and the clinician may also examine the cervix and check the baby's heartbeat. The NHS leaflet notes that a hematoma occasionally cannot be seen on a scan even when it is present.

When you attend with bleeding, the NHS says you will be asked about your symptoms, how many weeks pregnant you are and any earlier bleeding or pregnancies, so bring your maternity notes if you have them. Blood and urine tests may also be done, and some people are offered closer monitoring.

Often, yes. Cleveland Clinic says many heal on their own and some shrink over a few weeks, but there is no set timeline. ISUOG notes that the outlook is generally good, especially when there are no other signs such as cramping. The NHS leaflet states that most pregnancies affected by a subchorionic haematoma progress normally.

Sources also say it can occasionally be linked with a higher chance of miscarriage. The NHS leaflet lists a larger hematoma, older maternal age and diagnosis earlier in pregnancy as factors that raise that chance. These are group-level patterns, not a prediction for one pregnancy. Your care team weighs the size, the amount of bleeding, the baby's heartbeat and your history together.

Not always. The NHS leaflet says most people with an ongoing pregnancy in the womb need no extra follow-up. Repeat scans may be suggested when the hematoma is large compared with the pregnancy sac, when bleeding is moderate, heavy or ongoing, or after recurrent miscarriages. Cleveland Clinic also describes follow-up ultrasounds to track size in some cases.

If your blood group is RhD negative, ask whether you need an anti-D injection. The NHS leaflet notes it is offered for bleeding after 12 weeks, and Cleveland Clinic lists anti-D among possible treatments.

Advice varies between services, so follow what your own team tells you. The NHS leaflet says there is no evidence that bed rest helps, and suggests avoiding strenuous exercise and sex. Cleveland Clinic lists reducing exercise and heavy lifting, and avoiding sex, among options depending on the hematoma's size, position and stage of pregnancy. MedlinePlus advises avoiding intercourse after bleeding until your provider says it is safe, and checking with them before taking any medicine.

Ask how long any restriction should last and what would change the advice.

Writing these down before an appointment or phone call can help you leave with clear answers.

• How big is the hematoma compared with the pregnancy sac, and where is it?
• Did the scan show a heartbeat and a pregnancy in the expected place?
• Do I need a follow-up scan, and when?
• Am I RhD negative, and do I need anti-D?
• Which activities should I avoid, and for how long?
• Which kind of bleeding or pain should make me call you, and which needs emergency care?

On SameCase, patients and verified doctors share de-identified cases. Reading how others with a subchorionic hematoma described their scans, follow-up plans and questions can help you notice what to ask your own team. Every pregnancy is different, so other people's stories cannot predict yours or replace your care team's advice.

If a later scan raises a question about where the placenta sits, our guide on low-lying placenta at 20 weeks covers that separate finding.