Bleeding in early pregnancy: subchorionic hematoma
Bleeding in early pregnancy is frightening, but a subchorionic hematoma is common. Get the real facts on risk, healing, and the warning signs that matter.
In short
A subchorionic hematoma is a pocket of blood between the membrane around your baby and your uterus wall. It's the most common cause of bleeding between 10 and 20 weeks. Many people have one with no bleeding at all. Your risk goes up mainly in two cases. One: the hematoma covers 25% or more of the space around your baby's sac. Two: it sits behind the placenta. Call your doctor right away if bleeding increases. Also call if you get cramps or contractions, feel dizzy, or notice any change from how you've been feeling.
Sourced from StatPearls/NCBI Bookshelf, Cleveland Clinic · Updated August 15, 2026
Seeing blood during early pregnancy is scary. It can send you straight into worst-case thinking. You may have been told you have a subchorionic hematoma. That's a pocket of blood between the membrane around your baby and your uterus wall. Here is something to hold onto: it's the most common cause of bleeding between 10 and 20 weeks of pregnancy. It shows up in roughly 11% of bleeding cases in that window. Common doesn't mean unimportant. But it does mean your care team has seen this before and knows how to manage it.
This article walks through what a subchorionic hematoma actually is. It explains why so many people have one without ever noticing a drop of blood. It covers what raises the risk and what doesn't. Most importantly, it covers the specific signs that mean you should call your provider right away instead of waiting. The goal isn't vague reassurance. It's clarity, so you know exactly what to watch for and what you can let go of worrying about.
What is a subchorionic hematoma, exactly?
A subchorionic hematoma is sometimes called a subchorionic hemorrhage. It's a pocket of blood that collects beneath the chorion, one of the membranes around your growing baby. It sits between the chorion and the wall of your uterus. It happens because the chorion has partly pulled away from the uterine wall in that spot.
This is why doctors group it under early pregnancy bleeding. The blood comes from that separated space, not from the placenta or the baby. It's also the single most common explanation when someone bleeds between 10 and 20 weeks of pregnancy. About 11% of bleeding cases in that window are due to it.
Why might I not notice it at all?
Here's something that surprises a lot of people: most subchorionic hematomas cause no bleeding at all. Most people find out they have one by accident. It's spotted on a routine ultrasound done for a completely different reason.
Belly pain is also usually absent. Most people with a subchorionic hematoma have only light bleeding, or are asymptomatic (have no symptoms at all). A smaller group does get cramping or contractions. But that's the exception, not the rule. If your ultrasound found one and you feel fine, that's a normal and common way for this to show up.
Who is more likely to get one?
There isn't always a clear reason a subchorionic hematoma forms. But a few things make it more likely. These include a uterine malformation (an unusual shape of the uterus), a history of repeated pregnancy loss, or a pelvic infection. If one of these applies to you, it doesn't mean a hematoma is guaranteed. It just means your provider may watch things more closely.
It's also worth saying plainly: plenty of people with none of these risk factors get a subchorionic hematoma too. This isn't something you caused. Having one isn't a sign you did anything wrong in your pregnancy.
Does size or location change my risk?
Not all subchorionic hematomas carry the same level of concern. This is where the real, useful detail lives. The risk of pregnancy loss rises when the hematoma makes up 25% or more of the volume of the sac around your baby. Below that size, the picture looks less concerning.
Location matters too. A hematoma sitting behind the placenta is called retroplacental. It carries a higher risk of a poor outcome than one at the edge of the sac. Your provider will note both the size and position on your ultrasound report. Those two details are a big part of how they'll decide next steps.
Healing doesn't follow one script either. There's no fixed timeline for a subchorionic hematoma to resolve. Some shrink and disappear within a few weeks with no problems. Others are larger and need continued medical attention. Smaller hematomas with only minimal bleeding rarely cause problems at all.
When should I call my doctor right away?
Once you've been diagnosed with a subchorionic hematoma, some changes mean you should call your provider right away, instead of waiting for your next visit:
• Your symptoms change in any way from what you've been experiencing
• The amount of bleeding increases
• You develop contractions or cramping
• You feel dizzy or lightheaded
None of these automatically mean the worst. But they are the specific signals that tell your care team it's time to check in — so keep this list somewhere you'll remember.
What happens next, and does this change the rest of my pregnancy?
Picture a stable pregnancy: you're stable, your baby is stable, and there's no sign of major blood loss. For this case, the standard approach is conservative. Doctors watch and wait, with follow-up ultrasounds to track how it's changing, rather than giving active treatment. That's not your provider being dismissive. It's the evidence-based approach for a situation that, when stable, tends to resolve well on its own.
It's also worth understanding what a subchorionic hematoma does and doesn't change about the rest of your pregnancy. It does raise the risk of miscarriage, particularly at the size and location described above. But if your pregnancy continues, having had a subchorionic hematoma does not appear to affect your chance of early delivery or how you deliver. In other words, once you're past it, it's past you. It doesn't rewrite the rest of your pregnancy.
Frequently asked questions
Does having a subchorionic hematoma mean I'm going to miscarry?
Not necessarily. A subchorionic hematoma does raise the risk of pregnancy loss. But that risk rises when the hematoma makes up 25% or more of the volume of the gestational sac. Outcomes also tend to be worse when the hematoma sits behind the placenta (retroplacental) rather than at the edge of the sac. Many hematomas are smaller than that threshold. In a stable pregnancy, these are managed conservatively — watched with follow-up ultrasound.
Will a subchorionic hematoma mean I need an early delivery or a C-section?
If your pregnancy continues past the hematoma, the evidence doesn't show it affecting your rate of early delivery or your mode of delivery. A subchorionic hematoma raises miscarriage risk. But it isn't shown to change how or when you deliver once the pregnancy is ongoing.
How long does it take for a subchorionic hematoma to resolve?
There's no fixed timeline. Some hematomas shrink and resolve on their own within a few weeks without problems. Others are larger and need more medical follow-up. Small hematomas with minimal bleeding rarely go on to cause problems.
I was told I have a subchorionic hematoma but I've never had any bleeding — is that normal?
Yes. Most people with a subchorionic hematoma have no bleeding at all. They only find out about it by chance, during a routine ultrasound. Belly pain is also usually absent. Most people are either asymptomatic (have no symptoms) or have only light bleeding, though a minority do experience cramping or contractions.
What actually causes a subchorionic hematoma, and am I at higher risk?
It happens when the chorion membrane partly detaches from the uterine wall. Blood then collects in the space that opens up between them. Certain things can make this more likely, including a uterine malformation, a history of repeated pregnancy loss, or pelvic infections. But many people with none of these risk factors develop one too.
Sources
- A subchorionic hemorrhage/hematoma is bleeding that collects beneath the chorion membrane, in the space between the chorion membrane and the wall of the uterus, caused by partial detachment of the chorion from the uterine wall. — StatPearls/NCBI Bookshelf
- Subchorionic hemorrhage/hematoma is the most common cause of vaginal bleeding in patients who are 10 to 20 weeks pregnant, accounting for about 11% of cases in that gestational age range. — StatPearls/NCBI Bookshelf
- With a subchorionic hematoma, abdominal pain is usually absent — most patients present with only light vaginal bleeding or are entirely asymptomatic, discovered incidentally on ultrasound, though a minority do experience cramping or contractions. — StatPearls/NCBI Bookshelf
- A uterine malformation, a history of recurrent pregnancy loss, or pelvic infections are possible risk factors that predispose someone to developing a subchorionic hemorrhage. — StatPearls/NCBI Bookshelf
- For a stable pregnant patient with a stable fetus and no evidence of significant blood loss, the appropriate management of a subchorionic hematoma is conservative — watching and waiting with follow-up ultrasound rather than active intervention. — StatPearls/NCBI Bookshelf
- A subchorionic hematoma raises the risk of pregnancy loss specifically when it makes up 25% or more of the volume of the gestational sac, and the risk of a poor outcome is higher when the hematoma is located behind the placenta (retroplacental) rather than at the margin of the sac. — StatPearls/NCBI Bookshelf
- A subchorionic hematoma increases the risk of miscarriage, but if the pregnancy continues, the rate of premature delivery and the mode of delivery are not affected by having had the hematoma. — StatPearls/NCBI Bookshelf
- If diagnosed with a subchorionic hematoma, a patient should contact their healthcare provider if their symptoms change, the amount of bleeding increases, they develop contractions or cramping, or they feel dizzy or lightheaded. — Cleveland Clinic
- Most people with a subchorionic hematoma have no bleeding at all and only discover the hematoma incidentally during a routine ultrasound. — Cleveland Clinic
- There is no fixed timeline for a subchorionic hematoma to heal — in some cases it shrinks on its own within a few weeks without complications, while in others it can be large and require additional medical care; small hematomas with minimal bleeding rarely cause problems. — Cleveland Clinic
Educational information, not medical advice — always consult your doctor.