Venous Thromboembolism in Pregnancy

Pregnancy triggers many physiological changes, some of which increase the risk of certain health conditions. One major concern is venous thromboembolism (VTE), which includes deep vein thrombosis (DVT) and pulmonary embolism (PE). VTE can be life-threatening, but proper awareness and management significantly reduce the risks.

In this blog post, we will explore what venous thromboembolism is, why pregnancy increases the risk, its symptoms, and the steps that can be taken to prevent and treat this condition during pregnancy.

What is Venous Thromboembolism (VTE)?

VTE occurs when blood clots form in veins, potentially traveling through the bloodstream and causing complications. The two main types are:

1. Deep Vein Thrombosis (DVT): This occurs when a blood clot forms in one of the deep veins, typically in the legs. DVT can cause pain, swelling, and redness in the affected limb. If left untreated, DVT can lead to more serious complications.
2. Pulmonary Embolism (PE): If a blood clot from DVT breaks loose and travels to the lungs, it can block a pulmonary artery, leading to a pulmonary embolism. PE is a medical emergency and can cause shortness of breath, chest pain, and even sudden death if not treated promptly.

Why Are Pregnant Women at Higher Risk of VTE?

Several pregnancy-related changes contribute to a higher risk of VTE:

1. Increased Blood Coagulability: Pregnancy is a hypercoagulable state, meaning the blood’s ability to clot increases. This is a protective mechanism to reduce bleeding during childbirth, but it also raises the risk of clot formation in the veins.
2. Compression of Veins: As the pregnancy progresses, the growing uterus can put pressure on the veins in the pelvis and lower legs, particularly the inferior vena cava, which returns blood from the lower extremities to the heart. This can slow blood flow and increase the risk of clot formation.
3. Decreased Mobility: Pregnant women may be less active as they near their due date, which can contribute to blood pooling in the lower legs, increasing the likelihood of DVT.
4. Hormonal Changes: Hormones like progesterone and estrogen, which increase during pregnancy, can also contribute to a higher risk of clot formation. They can relax the walls of blood vessels and affect the balance of clotting factors in the blood.
5. Postpartum Period: The risk of VTE is especially high during the first six weeks after childbirth, as the body continues to recover from delivery and the blood still has a heightened tendency to clot.

Risk Factors for VTE in Pregnancy

Certain conditions increase the likelihood of VTE:

• Previous History of VTE: Women who have had DVT or PE in a previous pregnancy or at another point in their lives are at higher risk.
• Family History of Clotting Disorders: Inherited conditions such as Factor V Leiden mutation or antiphospholipid syndrome increase the risk of blood clots.
• Obesity: Being overweight or obese during pregnancy raises the risk of developing VTE.
• Multiple Pregnancy: Carrying twins, triplets, or more increases the strain on the circulatory system and the risk of clot formation.
• Advanced Maternal Age: Women over 35 years old are at higher risk for complications, including VTE.
• Cesarean Section: Women who have a C-section are at increased risk compared to those who deliver vaginally, due to prolonged immobility and surgical trauma.
• Prolonged Bed Rest: Women who are on bed rest due to complications like preeclampsia or placenta previa are at higher risk of VTE due to limited movement.
• Smoking: Smoking during pregnancy significantly increases the risk of clot formation.

Symptoms of Venous Thromboembolism

Recognizing the symptoms of VTE early can be life-saving. The signs and symptoms of DVT and PE may overlap, but each has distinct characteristics.

Symptoms of DVT (Deep Vein Thrombosis):

• Swelling in one leg (typically the calf or thigh)
• Pain or tenderness in the leg, especially when standing or walking
• Redness or warmth over the affected area
• Swollen veins that are visible just under the skin
• Leg cramps that don’t improve

Symptoms of PE (Pulmonary Embolism):

• Sudden shortness of breath
• Chest pain (sharp or stabbing, which may worsen with deep breathing)
• Rapid heart rate
• Coughing, sometimes with blood-tinged sputum
• Lightheadedness or fainting
• Sweating or feeling faint

If any of these symptoms occur, especially in the second or third trimester, seek immediate medical attention. Pulmonary embolism is a medical emergency, and prompt treatment can save lives.

Diagnosing Venous Thromboembolism in Pregnancy

If VTE is suspected, a healthcare provider will evaluate the patient’s medical history, perform a physical exam, and may order several diagnostic tests, including:

• Ultrasound: This is the most common imaging test used to diagnose DVT. It can help detect blood clots in the deep veins of the legs.
• CT Pulmonary Angiography: If PE is suspected, a CT scan can be used to look for clots in the pulmonary arteries of the lungs.
• Blood Tests: A D-dimer test may be used, although it’s not as reliable during pregnancy, as levels tend to be elevated even in healthy pregnancies.

Managing and Treating VTE During Pregnancy

The treatment of VTE during pregnancy involves a careful balance between preventing clot growth and ensuring the safety of both the mother and baby. Treatment typically includes:

1. Anticoagulant Medications: Blood thinners such as heparin or low-molecular-weight heparin (LMWH) are the primary treatments for VTE during pregnancy. These medications help prevent the clot from growing and reduce the risk of new clots forming. Oral anticoagulants like warfarin are generally avoided during pregnancy due to the risk of birth defects, but LMWH is considered safe.
2. Compression Stockings: These may be recommended to help reduce swelling and improve blood flow in the legs.
3. Monitoring: Women on anticoagulation therapy need regular follow-up with their healthcare provider to monitor blood clotting levels and adjust medication dosages as needed.
4. Delivery Planning: For women with a history of VTE or current DVT/PE, the delivery plan may need to include precautions such as avoiding certain types of anesthesia or using blood thinners during labor to reduce the risk of clotting complications.
5. Postpartum Anticoagulation: If a woman has had VTE during pregnancy, she may need to continue anticoagulation therapy for several weeks postpartum, as the risk of VTE remains elevated during the recovery period.

Preventing VTE During Pregnancy

While not all cases of VTE can be prevented, there are several steps that can help reduce the risk:

1. Prenatal Care: Regular prenatal visits are important for identifying risk factors and monitoring for early signs of VTE.
2. Mobility: Staying active, even with light exercise like walking, helps improve circulation and prevent blood from pooling in the legs. Avoid long periods of immobility, especially during travel.
3. Weight Management: Maintaining a healthy weight during pregnancy can help reduce the risk of developing VTE.
4. Compression Stockings: Wearing compression stockings can help promote blood flow in the legs and reduce swelling, especially in women at high risk.
5. Early Identification: If you have risk factors such as a history of clotting disorders or a previous VTE, your doctor may recommend blood thinners or other preventive measures during pregnancy.

Conclusion

VTE is a serious but manageable pregnancy complication. Recognizing symptoms, addressing risk factors, and following medical guidance significantly lower the dangers. Pregnant individuals should stay informed, attend regular prenatal visits, and take preventive steps to ensure a safe and healthy pregnancy. If you experience any VTE symptoms, seek immediate medical care.

If you’d like to learn more about the Maternal 911 Education System, click here.