Learning About Blood Clots and Pregnancy

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Back of legs showing deep veins, with detail of a blood clot formed in a vein.

What is a blood clot?

A blood clot is a clump of blood that forms in a blood vessel. Sometimes clots happen in deep veins. This is called deep vein thrombosis. It needs medical care right away. If a clot in a deep vein breaks apart, pieces of it can travel to the lungs. A blood clot in the lung is called a pulmonary embolism.

There's a higher risk for clots during pregnancy and after delivery. That's because of changes in hormones and blood flow. Having limited mobility also increases the risk.

What are the symptoms?

Symptoms of deep vein thrombosis (blood clot in a vein) include pain, swelling, redness or any change in color, or warmth in just one leg or arm. Symptoms of pulmonary embolism (blood clot in the lung) include shortness of breath and sharp chest pain that's worse when you cough or take a deep breath.

How is it diagnosed?

Your doctor will do a physical exam and ask questions about your past health. You may need certain tests, such as an ultrasound, an EKG (electrocardiogram), or a CT scan. You may also need blood tests.

How is it treated?

Blood clots in deep veins are most often treated with a blood thinner (anticoagulant). It can stop the clot from growing and prevent it from breaking and moving to the lungs. It can also prevent new clots from forming. Your doctor may also suggest things you can do to relieve some of your symptoms.

What increases your risk?

Changes in hormones and blood flow during pregnancy and after delivery increase the risk of blood clots. Other things that increase your risk include:

  • Having limited mobility.
  • Having a cesarean section or other recent surgery.
  • Having certain blood problems that make blood clot too easily.
  • Having a history of blood clots.
  • Smoking.
  • Being overweight.

Problems from blood clots during or after pregnancy are more common and more likely to cause death in people who are Black, American Indian, or Alaska Native. There is no simple reason why. Less access to good health care and differences in how patients are listened to and treated are part of it. Other health, economic, and social issues, including racism, also increase the risk for these groups. If you're a member of one of these groups, share your concerns with your doctor and talk about what you both can do to avoid problems.

What can you do to reduce your risk for problems?

  • Know the signs and symptoms.

    If you have any of the following symptoms, get help right away.

    • Swelling in one arm or leg (but not the other). This swelling is different from the swelling that's common in pregnancy.
    • Pain in the arm, calf, back of the knee, thigh, or groin.
    • A color change on the skin of the arm, leg, or groin. The skin may be reddish or purplish, depending on your usual skin color.
    • Shortness of breath or chest pain.
  • Know your family history, and share it.

    If a close family member has had blood clots, be sure your doctor knows.

  • Work with your doctor.

    Together, you can make a plan for how to reduce your risk. This is extra important if you are on bed rest or if you've had a C-section.

  • Follow your care plan.

    Take medicines as prescribed, and use compression stockings as directed.

  • Exercise.

    Talk with your doctor about what a safe amount of exercise is for you.

  • Avoid sitting for long periods of time.

    Get up and move around every hour or so. This is also important when you're traveling. During long trips, take time to walk around regularly to keep blood from settling in your legs. If you have limited mobility, try to move your legs or change position as best you can.

  • Drink plenty of liquids.

    Aim for about 10 glasses of liquid a day.

  • Take care of your health.
    • If you smoke, talk to your doctor about getting help to quit.
    • Talk with your doctor about what healthy weight gain looks like in your pregnancy.
  • Trust yourself, and be direct.

    You are the expert on your body. If something doesn't feel right, get help. If you don't feel like you're being heard, say so. You can say, "I know that pregnancy has risks. I want to be sure I'm getting good care." You could also ask a friend or family member to help you talk to your doctor. For some people, seeing a different doctor may be an option.

When should you call for help?

Call 911 anytime you think you may need emergency care. For example, call if:

  • You have symptoms of a blood clot in your lung (called a pulmonary embolism). These may include:
    • Sudden chest pain.
    • Trouble breathing.
    • Coughing up blood.

Call your doctor now or seek immediate medical care if:

  • You have symptoms of a blood clot in your arm or leg (called a deep vein thrombosis). These may include:
    • Swelling in one arm or leg (but not in the other) or in the groin.
    • Pain in the arm, calf, back of the knee, thigh, or groin.
    • A color change on the skin of the arm, leg, or groin. The skin may be reddish or purplish, depending on your usual skin color.

The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.