Pregnancy is an exciting and hopeful time, but it also brings changes to your body that may increase the risk of certain health conditions. One of the most serious conditions that can affect pregnant women is pulmonary embolism (PE), a condition where a blood clot blocks an artery in the lung.
“Blood clots that form in deep veins of the legs or pelvis, called deep vein thrombosis (DVT), can sometimes break free and travel to the lungs,” said Steven Calvin, MD, a maternal and fetal medicine physician with Banner - University Medicine. “When those clots create a blockage in the blood vessels of the lungs, it’s called a pulmonary embolism.”
Although rare, PE is a leading cause of pregnancy-related deaths in the United States. Women are five times more likely to develop a blood clot during pregnancy, childbirth and the three months following delivery.
Learn more about why pregnancy increases your risk of pulmonary embolisms, symptoms to watch for and steps you can take to prevent blood clots.
Why pregnancy raises your risk
Your body undergoes amazing changes during pregnancy. But some of these changes naturally raise your risk of blood clots:
- Hormones: “Pregnant women are at a higher risk for blood clots and pulmonary embolism because pregnancy hormones make their blood clot more easily,” Dr. Calvin said. “This is to protect the mother against hemorrhage at the time of delivery but also makes clots more likely.”
- Blood flow: The growing uterus presses against the veins in your pelvis, which slows blood flow from your legs back to your heart.
- Less movement: If you’re on bed rest, recovering from surgery (such as a C-section) or sitting for long periods, your circulation slows down.
Risk factors to be aware of
Every pregnant person has an increased risk of blood clots, but some people are at even greater risk. Knowing your risk factors can help you and your care team take steps to keep you safe and healthy.
General pregnancy-related risks
- Hormone changes that increase clotting
- Pressure from the uterus slows blood flow
- Long periods of sitting, bed rest or travel
Higher risk categories
- Personal or family history of blood clots (venous thromboembolism or VTE)
- Cesarean section delivery
- Obesity (BMI over 40)
- Being over age 35
- Carrying twins, triplets or more
- Smoking
- Medical conditions such as thrombophilia, autoimmune diseases, irritable bowel syndrome or varicose veins
- Prolonged hospitalization or immobility
“There are also inherited conditions that raise the chance of developing abnormal blood clots,” Dr. Calvin said. “These include antiphospholipid syndrome, homozygous Factor V Leiden and others.”
Signs and symptoms to watch for
Blood clots may not always cause symptoms, but knowing the warning signs can save lives.
Possible signs of DVT
- New swelling in the leg, calf or thigh
- Pain or tenderness not caused by injury
- Skin that feels warm, red or discolored
Possible signs of PE
- Sudden shortness of breath
- Chest pain that gets worse with a deep breath or cough
- Rapid or irregular heartbeat
- Coughing up blood
- Lightheadedness or fainting
Seek medical help right away if you experience these symptoms.
Diagnosing and treatment
An ultrasound is commonly used to check for DVT in the legs. If PE is suspected, imaging tests such as a ventilation-perfusion (V/Q) scan or CT pulmonary angiography may be recommended, with precautions taken for you and your baby.
Treatment will depend on how serious the clot is and your overall health during pregnancy:
Blood thinners (anticoagulants)
“Pregnant women with a high risk of DVT and PE are usually prescribed medications such as Lovenox or regular heparin, two types of a blood thinner that decrease the blood’s ability to clot,” Dr. Calvin said.
These medications don’t dissolve existing blood clots but stop them from growing and help prevent new ones from forming.
Learn more about taking blood thinners.
Thrombolytics (clot-busting drugs)
In emergencies, thrombolytics may be given to break up the clot quickly. These drugs carry a higher risk of bleeding, so they are used only when necessary.
Surgery or catheter procedures
In rare cases, surgery may be needed to remove the clot directly, or a catheter may be used to deliver medicine into the blood vessel. These treatments are considered only if other options are not enough.
Most people respond well to treatment, especially if a PE is found early.
What you can do to prevent blood clots
You can take steps to lower your risk of blood clots during and after pregnancy.
Lifestyle habits
- Stay active and try to walk every day
- Avoid sitting or standing still for long stretches of time
- Drink plenty of water
- Wear compression stockings if your provider recommends them
- During long flights or car rides, take breaks to stretch your legs and walk around
- Avoid unhealthy habits like drinking and smoking
Dr. Calvin also noted that omega-3 fatty acids are helpful. “Omega-3 lipids are beneficial in pregnancy, as well as for the developing baby,” he said. “They can also decrease the clotting tendency of blood in a natural way.”
Medical prevention
If your risk is slightly higher, your provider may recommend a low dose of aspirin.
“If you are at high risk, you may be prescribed a blood thinner such as heparin or Lovenox,” Dr. Calvin said. “These medicines are safe in pregnancy and not harmful to your baby.”
After a cesarean birth, you may use special leg compression devices to help blood keep moving and lower the risk of clots.
When to call your provider
Call your health care provider if you notice swelling, pain or tenderness in your leg. Go to the ER or call 911 right away if you have chest pain, sudden shortness of breath or coughing up blood. It’s always better to get checked because early treatment saves lives.
Bottom line
Pulmonary embolism in pregnancy is rare but serious. By knowing your risk factors, staying active and recognizing the warning signs, you can protect yourself and your baby.
If you have questions about your risk, talk to your provider or a Banner Health specialist.
