A pregnant person getting an ultrasound
By Kathleen Kennedy, MD

Blood Clots During Pregnancy: Symptoms & Risks

Blood clots are rare but they are the leading cause of maternal death during pregnancy. Learn about common risk factors and detect the symptoms of a blood clot sooner

Blood clots are rare and serious if they occur. Women are five times more likely to develop a blood clot during pregnancy and for three more months after giving birth. Blood clots are a leading cause of maternal death during pregnancy.

When blood hardens into a gel-like clump of blood, it forms a clot. This is a normal body reaction to prevent too much bleeding if you are injured. But if one breaks loose and moves to other parts of the body, this is an emergency.

A blood clot that breaks off can block blood and oxygen supply to the baby or to your brain, lungs or other important parts of the body. If left untreated, it can cause a heart attack, stroke, miscarriage or another serious breathing condition.

Your doctor may call a blood clot a venous thromboembolism (VTE). According to the American Pregnancy Association (APA), blood clots affect 1-2 out of 1,000 women. Pregnancy increases the risk for blood clots due to normal hormonal changes, such as higher levels of estrogen.

A blood clot can happen to anyone, even if they are otherwise health. Tennis star Serena Williams developed life-threatening blood clots in her lungs after delivering her baby. A sudden shortness of breath and coughing fits prompted her to check in with her doctor. If something doesn’t feel right, continue to ask for help. Make sure you are heard. For Serena, the blood clots were caught in time, and she survived.

Go to the emergency room or call 911 if you suspect a blood clot. Prompt treatment for blood clots reduces the risk of serious complications.

Recognize the Signs of a Blood Clot

Spotting the signs of a possible blood clot and seeking help reduces the risk of complications for you or your pregnancy. Pulmonary embolism (PE) and deep vein thrombosis (DVT) are two types of blood clots that can form in pregnancy.

Pulmonary Embolism (PE)

A PE is when a blood clot travels to the lung, where it blocks an artery. It can be fatal if it is not treated immediately. PE is associated with 10-15% of pregnancy-related deaths in the U.S. It can also cause long-term lung and other organ damage.

PE symptoms may include:

  • Chest pain (stabbing)
  • Dizziness or fainting
  • Dry cough with blood
  • Fever
  • Excessive sweating
  • Sudden shortness of breath
  • Redness or bluish color in the skin (from lack of oxygen)
  • Unusual swelling or pain in the legs

Deep Vein Thrombosis (DVT)

A DVT is a blood clot in the veins of the legs or pelvic area. A DVT needs quick treatment to prevent a PE from occurring.

DVT symptoms may include:

  • Pain in the back of the leg (usually the calf) not caused by an injury
  • Red or warm skin at the affected area
  • Tender or numb legs
  • Unusual swelling in the legs, usually below the knee
  • Veins that bulge or appear larger than usual

Diagnosis & Treatment

To diagnose a blood clot, a doctor will conduct a physical exam and blood tests. If a blood test doesn’t rule out the possibility of a blood clot, you will need an ultrasound or CT scan to locate and determine the severity of the clot.

Treatment generally includes a blood thinning medication such as heparin, an anticoagulant considered safe during a pregnancy. Medication will not dissolve the clot. It helps by lowering the clotting ability of the blood. It can also prevent an existing blood clot from getting bigger.

You may be referred to an anticoagulation clinic for ongoing treatment. If the clot is life-threatening, a doctor may perform a procedure to remove the clot with a catheter or vein filter.

You cannot prevent a blood clot. But there are ways to reduce your risk for developing one.

Reduce the Risk

Understanding your risk factors is the first step to reduce your risk. The likelihood for developing a blood clot increases with the more risk factors you have, such as:

  • Bed rest or insufficient movement
  • Delivery by C-section
  • Diabetes
  • Family history of blood clots
  • Health conditions in the heart or lungs
  • Pregnant at age 35 or older
  • Previous blood clot(s)
  • Overweight or obese
  • Smoke, or regular secondhand smoke
  • Use of hormone fertility treatments

The Centers for Disease Control and Prevention (CDC) provides this helpful blood clot prevention checklist for pregnant people. Take the checklist to your next OB-GYN appointment. Your doctor will work with you to reduce your risk, as needed.

You are your best advocate. If you feel “off”, tell your doctor. And if you aren’t getting the care you need, get a second opinion.

Ask your healthcare provider if you have concerns. A blood clotting disorder can be affiliated with a dangerous high blood pressure condition in pregnancy called preeclampsia. There are steps you can take to minimize your risk.

Getting pregnant at a healthy weight is one of the most effective ways to reduce the risk of blood clots during pregnancy. A typical recommended BMI is between 18.5 and 25 before getting pregnant, when possible.

Once pregnant, try to limit your weight gain to the amount your doctor recommends. Often this is between 25-35 pounds. This will vary, depending on your situation and starting weight. Every pregnancy is unique. Your doctor will provide with you information about your ideal pregnancy weight.

You can also help reduce your risk for blood clots with these consistent, healthy habits while pregnant:

  • Exercise: Limit how hard or often you exercise based on your doctor’s recommendation.
  • Compress: Wear compression socks or support hose to promote circulation.
  • Hydrate: Drink plenty of fluids (10 8-oz. glasses daily).
  • Medicate: Take any medications prescribed by your doctor (such as heparin).
  • Move: Change positions of legs and feet frequently to improve blood flow if sitting for a long time.
  • Reduce: Avoid unhealthy habits. Try to quit smoking, if possible.

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Reach Out for Help

Call your doctor if you experience any of the following:

  • Chest pain
  • Coughing up blood
  • Rapid or racing heart rate
  • Shortness of breath or difficulty breathing

We are here to support and monitor you and your baby’s health, throughout your pregnancy and beyond. It is important for you to attend all recommended prenatal appointments. In between appointments, if you worry that you may have a blood clot, call your doctor right away.

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Categories: Women's Health