Pregnancy Information Complications Deep Vein Thrombosis

Pregnancy increases the risk of deep vein thrombosis (blood clots) and pulmonary embolism. While deep vein thrombosis does not directly endanger the developing fetus, pulmonary embolism can affect fetal health.

Pregnancy and Deep Vein Thrombosis

Deep vein thrombosis describes the formation of blood clots in blood vessels. Most cases of deep vein thrombosis occur when blood clots form in the large veins of the legs and pelvis.

Pregnant women are more susceptible to deep vein thrombosis than non-pregnant women. Pregnancy causes hormonal changes that increase blood coagulability, a measure of how easily blood clots. In addition, the expanding uterus puts pressure on blood vessels, restricting blood flow from the legs and pelvis back to the heart. Slower blood flow increases the risk of deep vein thrombosis.

Pregnant Women and Deep Vein Thrombosis Risk Factors

Pregnancy itself increases the risk of deep vein thrombosis. The development of blood clots in a previous pregnancy increases the chance of deep vein thrombosis in a future pregnancy. Inherited blood clotting difficulties also increase the chances of deep vein thrombosis in pregnant women.

While pregnant women are at increased risk of deep vein thrombosis, the end of pregnancy does not immediately reduce the risk. In fact, the period after pregnancy has an even higher risk of deep vein thrombosis than the pregnancy itself, until the woman’s hormonal levels return to their pre-pregnancy state.

Blood Clots and Pulmonary Embolism in Pregnancy

Blood clots that break away from blood vessels may travel through the blood vessels of pregnant women and reach the lungs. In the lungs, blood clots can impair oxygen flow to the rest of the body. This is called a pulmonary embolism.

A pulmonary embolism is a medical emergency, and can threaten the life of the pregnant woman. If left untreated too long, pulmonary embolism causes low blood pressure and low oxygen levels that damage the fetus.

Treating Pulmonary Embolism and Deep Vein Thrombosis

Warfarin, one of the most common medications for deep vein thrombosis, causes birth defects, so it cannot be used during pregnancy. Pregnant women diagnosed with deep vein thrombosis are treated with heparin injections, which dissolve blood clots with less risk of fetal damage.

Like deep vein thrombosis, pulmonary embolism is treated with blood thinners to dissolve blood clots. Care must be taken if the pregnancy is in its last stages, as administering blood thinners at this point of pregnancy increases the risk of heavy bleeding during labor.

Symptoms of Deep Vein Thrombosis and Pulmonary Embolism

Pregnant women should learn to identify symptoms of deep vein thrombosis and pulmonary embolism. Early detection of blood clots lowers the chance of pregnancy complications due to pulmonary embolism. Deep vein thrombosis symptoms include pain and swelling at the blood clot’s location. Blood clots may also cause redness and tenderness around the site.

Pulmonary embolism symptoms differ markedly from deep vein thrombosis symptoms. Pulmonary embolism symptoms include:

  • difficulty breathing
  • anxiety
  • chest pain
  • coughing or breathing deeply, causing chest pain
  • feeling lightheaded
  • loss of consciousness.

Pregnant women who experience pulmonary embolism symptoms should seek immediate medical attention.


Beers, M. H.,