Before the days of sophisticated medical imaging, countless women sailed through seemingly perfect pregnancies and delivered healthy babies without ever knowing they had complications like a uterine blood clot.

But with the advent of pregnancy ultrasounds, you're now much more likely to find out (and worry) about these types of occurrences. A blood clot in the uterus isn't usually a major cause for concern, though. Here's what to expect if one is detected.

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Key Takeaways
  • Most uterine blood clots in early pregnancy are usually not dangerous. While hearing the diagnosis can be scary, they’re rarely linked to miscarriage or long-term pregnancy complications.
  • They may cause spotting, but the exact cause isn’t always clear. A uterine blood clot forms after some bleeding in the uterus, possibly from a ruptured blood vessel or a minor placental separation. Early monitoring with ultrasound helps doctors manage any potential risks.
  • Rest and monitoring are typically the main treatment — and outcomes are often positive. Doctors may recommend limiting exercise, pelvic rest, and follow-up ultrasounds. Many women with uterine blood clots go on to have healthy, full-term pregnancies.

What are uterine blood clots?

Most blood clots that turn up on first-trimester sonograms are what doctors call subchorionic hematomas (SCH). In plain English, that means a collection of blood located between the wall of your uterus and your baby's gestational sac (also known as the chorionic membrane).

Uterine blood clots are no different from clots elsewhere in the body: They form from coagulated blood cells and proteins.

"I had an SCH with my daughter," says What to Expect Community member MerlotMorgan. "Mine was located right behind my placenta and it pushed on it slightly. I just took it easy for the remainder of my pregnancy and welcomed my daughter at just over 39 weeks. She's now a happy and healthy 8.5-month-old."

What causes a blood clot in the uterus?

If you have a uterine blood clot, it means there was bleeding in your uterus at some point, which sounds more ominous than it usually is. Sometimes clots cause noticeable vaginal spotting or bleeding, which is quite common in early pregnancy.

What caused the bleeding? It’s hard to be certain. It may have been a ruptured blood vessel. Or the hematoma may have slightly separated the placenta from the uterine wall — a condition called a placental abruption. With early diagnosis and monitoring, your doctor can help reduce potential risks for you and your baby.

What does a uterine blood clot mean for my pregnancy?

Hearing that you have a blood clot during pregnancy can feel frightening. But first trimester blood clots are rarely associated with miscarriage or problems later in pregnancy.

Over time, the clot may be reabsorbed into the uterus, or it may just loiter around harmlessly until your baby is born. At a follow-up visit, your doctor will likely perform another ultrasound to check on it. As long as the pregnancy is progressing nicely, you’re at no higher risk of complications because of the clot.

"I had a SCH from week 6 all the way to week 34... it was 22 centimeters!" says What to Expect Community mom ftmmomnov. "I had a weekly ultrasound to be at peace."

In the meantime, follow your doctor’s advice regarding activity restriction. You may be asked to limit exercise and follow pelvic rest (meaning no vaginal exams or pregnancy sex). Most importantly, try to keep worry in check.

"This [bleeding from a blood clot] happened to me at 13 and 15 weeks. Bed rest and full pelvic rest and minimizing stress helps a lot," says What to Expect Community member nmj1023. "It is so scary though, and it's hard not to be stressed!"

If those middle-of-the-night worries creep in, the What to Expect app is always there with expert answers, community support, and a little extra peace of mind — right in your pocket.