What is Pulmonary Embolism in Pregnancy?

A pulmonary embolism occurs when a blood clot, usually formed in a deep vein in the leg or pelvis, breaks away and travels through the bloodstream to the lungs. When the clot becomes lodged in a blood vessel in the lungs, it can partially or completely block blood flow. This can reduce oxygen supply and place significant strain on the heart and lungs. A pulmonary embolism is a medical emergency and requires prompt treatment.
Most pulmonary embolisms begin with a condition called deep vein thrombosis (DVT). In DVT, a blood clot forms in a deep vein, usually in the leg. If part of the clot breaks away and travels to the lungs, it can cause a pulmonary embolism. Therefore, identifying and treating blood clots early, while they are still in the leg, is important.
Pregnancy itself increases the risk of developing blood clots. This risk increases further during the weeks immediately after delivery.

Why Pregnancy Increases the Risk of Pulmonary Embolism?

During pregnancy, the body naturally prepares for the blood loss that can occur during childbirth by making the blood more likely to clot. Although this helps reduce excessive bleeding during delivery, it can also increase the risk of unwanted blood clots.
Several factors contribute to this increased risk:

The body produces higher levels of clotting factors during pregnancy, making the blood more likely to clot.
As the baby grows, the uterus can put pressure on the veins in the pelvis. This can slow blood flow from the legs back to the heart and increase the likelihood of clot formation.
Prolonged periods of inactivity, including bed rest, recovery after a C-section, or sitting for several hours during travel, can further slow blood circulation and increase the risk of blood clots.

Every pregnant woman has some increased risk of developing blood clots simply because of pregnancy. Therefore, it is important to be aware of the symptoms, even if there are no other known risk factors.

What are the Symptoms of Pulmonary Embolism During Pregnancy?

Pregnancy can normally cause symptoms such as breathlessness, tiredness, and an increased heart rate. As a result, the early symptoms of pulmonary embolism may sometimes be mistaken for normal pregnancy-related changes. However, sudden or unusual symptoms should not be ignored.
Common symptoms of pulmonary embolism include:

Sudden shortness of breath or rapid breathing: Unlike the gradual breathlessness that may occur later in pregnancy, this symptom develops suddenly and may feel unusual or severe.
Chest pain that may worsen with deep breathing: The pain may feel sharp or stabbing and can become worse when taking a deep breath or coughing.
Fast heart rate (tachycardia): A pulmonary embolism can cause the heart to work harder, resulting in a noticeably fast or pounding heartbeat.
Coughing, sometimes with bloody mucus: A cough, particularly one accompanied by blood-stained or blood-tinged mucus, requires prompt medical assessment.
Dizziness, lightheadedness, or fainting: Reduced blood flow and oxygen levels may cause sudden dizziness or lightheadedness.
Pain, swelling, or redness in one leg: These are the signs of DVT, which can lead to pulmonary embolism if part of the clot travels to the lungs.

Seek emergency medical care immediately if you develop sudden unexplained breathlessness, chest pain, coughing up blood, fainting or collapse. If you develop new swelling, pain, warmth or redness in one leg without chest or breathing symptoms, contact a doctor urgently for assessment.

Pregnancy Risks and Causes of Pulmonary Embolism in Pregnancy[DA1]

Pregnancy increases the risk of blood clots because of several overlapping factors, including:

Hormonal changes: Changes in hormone levels during pregnancy increase the levels of certain clotting factors, making the blood more likely to clot.
Physical pressure: As the uterus grows, it can put pressure on the veins in the pelvis and legs. This can slow the flow of blood back to the heart and contribute to clot formation.
Additional risk factors: Some women have a higher risk of developing blood clots than others. Factors such as being 35 or older, having a personal or family history of blood clots, having excess weight, and prolonged immobility or bed rest can further increase the risk.

Signs to Watch For: DVT During Pregnancy

Since many pulmonary embolisms begin with a blood clot in the leg, recognising the signs of DVT is important.
Possible symptoms include swelling in one leg, warmth over the affected area, redness or skin discolouration, and a dull ache or tightness in the calf without an obvious cause.
A DVT does not always develop into a pulmonary embolism. However, early diagnosis using tests such as compression ultrasound can help doctors begin treatment before the clot has an opportunity to travel to the lungs.

Is Pulmonary Embolism Dangerous for the Baby?

One of the most common concerns for expecting mothers is whether pulmonary embolism can affect the baby.
The blood clot itself does not directly travel into the baby’s circulation. However, a pulmonary embolism can indirectly affect the baby if it reduces the mother’s oxygen levels or places significant strain on her heart and lungs. If these problems are not treated promptly, they may affect the delivery of oxygen and nutrients to the baby through the placenta.
When pulmonary embolism is diagnosed and treated promptly, many pregnancies can continue safely. Doctors may closely monitor both the mother and baby throughout treatment.

How is Pulmonary Embolism Diagnosed During Pregnancy?

If DVT symptoms are present, doctors may use compression ultrasound to look for a clot in the leg. When pulmonary embolism is suspected, tests may include a chest X-ray followed by a CT pulmonary angiogram (CTPA) or ventilation-perfusion (V/Q) scan. The medical team selects the most appropriate test after considering the clinical situation and the risks of leaving a possible PE undiagnosed.

What are the Treatment Options for Pulmonary Embolism in Pregnancy?

Treating pulmonary embolism during pregnancy involves effectively managing the blood clot while considering the safety of both the mother and baby. Treatment may include:

Low molecular weight heparin (LMWH): LMWH is commonly used to treat blood clots during pregnancy because it does not cross the placenta. Warfarin is generally avoided during pregnancy because it can affect the developing baby.
Hospital care for severe cases: People with severe pulmonary embolism may require oxygen support, close monitoring, and specialised hospital care. In rare, life-threatening cases, doctors may consider treatments such as clot-dissolving therapy under specialist supervision.
Planning around delivery: Because anticoagulant medicines can increase the risk of bleeding, the timing of treatment may need to be carefully planned around labour and delivery.
Treatment after delivery: The risk of blood clots remains elevated after childbirth. For a confirmed DVT or PE, anticoagulant treatment is usually continued for at least six weeks after birth and for a minimum total treatment period of three months. The exact duration is decided by the treating medical team.

Treatment decisions should always be made by a healthcare team experienced in managing blood clots during pregnancy and should take into account the health and safety of both the mother and baby.

Why Choose Narayana Health?

Managing pulmonary embolism during pregnancy may require coordinated care from obstetricians and pulmonologists. At Narayana Health, expecting mothers have access to multidisciplinary teams, advanced diagnostic facilities, and maternal-fetal monitoring for high-risk pregnancies.
From risk assessment and diagnosis to treatment and postpartum follow-up, coordinated care focuses on supporting the health and safety of both the mother and baby.

Conclusion

Pulmonary embolism during pregnancy is a serious condition, but prompt diagnosis and treatment can significantly improve outcomes. Understanding why pregnancy increases the risk of blood clots and recognising warning signs such as sudden breathlessness, chest pain, or swelling in one leg can help ensure timely medical attention.
If you experience sudden or unusual symptoms that could indicate a pulmonary embolism, seek immediate medical care rather than waiting for the symptoms to improve.

References

Centers for Disease Control and Prevention. Understanding your risk for blood clots with pregnancy [Internet]. Atlanta (GA): CDC; 2024 May 15 [cited 2026 Sep 11]. Available from: https://www.cdc.gov/blood-clots/risk-factors/pregnancy.html
Royal College of Obstetricians and Gynaecologists. Diagnosis and treatment of venous thrombosis in pregnancy and after birth [Internet]. London: RCOG; [cited 2026 Sep 11]. Available from: RCOG

FAQs

Q. Can pulmonary embolism be treated without harming the baby?
A. Yes. Low molecular weight heparin is commonly used during pregnancy because it does not cross the placenta. Doctors select and monitor treatment carefully to manage the blood clot while considering the safety of both the mother and baby.

Q. What is the difference between DVT and PE?
A. Deep vein thrombosis (DVT) is a blood clot that forms in a deep vein, usually in the leg. Pulmonary embolism (PE) occurs when part of the clot breaks away and travels to the lungs, where it can block blood flow and become life-threatening.

Q. Should I be worried if I have leg swelling during pregnancy?
A. Mild swelling in both legs can be common during pregnancy. However, swelling in one leg, particularly when accompanied by pain, warmth, redness, or tenderness, should be evaluated by a doctor because it may indicate DVT.

Q. Can I fly while pregnant if I am at risk of blood clots?
A. Many pregnant women can travel by air safely with appropriate precautions. These may include staying hydrated, moving around regularly during the flight, and using compression stockings if recommended by a doctor. Women with a higher risk of blood clots should discuss travel plans with their doctor before flying.