Pregnancy increases the risk of deep vein thrombosis (DVT), which can result in complications that affect the pregnant person and the fetus. Managing DVT or reducing blood clot risks is important to prevent complications during pregnancy and childbirth.

A pregnant person is five times more likely to experience a blood clot compared to those who are not pregnant. People will need to contact a doctor as soon as possible if they have any DVT symptoms.

This article looks at how DVT can affect pregnancy and delivery, risk factors, treatment, and prevention.

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According to the Centers for Disease Control and Prevention (CDC), a person is more likely to experience a blood clot during pregnancy, childbirth, and up to 3 months after delivery.

This is because:

  • natural changes during pregnancy cause the blood to clot more easily to reduce the chance of blood loss during delivery
  • the growing fetus presses on the blood vessels around the pelvis, resulting in less blood flow to the legs
  • bed rest after delivery limits a person’s movement, limiting the blood flow in the legs and arms

Risk factors for developing blood clots during or after pregnancy include:

  • a personal or family history of blood clots, or a blood clotting disorder
  • overweight or obesity
  • being pregnant at 35 years old or above
  • smoking
  • having a cesarean section (C-section) delivery
  • prolonged periods of reduced movement, such as bed rest, travel, or recovery after childbirth or surgery
  • certain conditions in pregnancy, including pregnancy with multiple babies or using hormone fertility treatments

A DVT can impact pregnancy in various ways, including before, during, and after delivery.

Pregnant person

During pregnancy, blood clots may increase the risk of:


Blood clots may be potentially harmful to a fetus and may cause:

  • intrauterine growth restriction, which is when the fetus does not grow as expected
  • blood clots in the placenta, which may stop blood flow to the fetus
  • placental insufficiency, which prevents a fetus from getting enough food and oxygen


Surgery for cesarean delivery may double the risk of serious blood clots.

For those taking blood thinners, it is still possible to have a safe delivery. To reduce the bleeding risk, a doctor may need to stop blood thinning medications a few hours before delivery. This also allows people to get an epidural.

Compression devices on the arms and legs may also help improve blood flow during delivery.

After delivery

The risk of serious blood clots continues for up to 3 months after delivery.

According to the National Blood Clot Alliance, the highest risk of developing a blood clot is in the 6 weeks after delivery.

If people have DVT, they will need to continue taking blood thinning medication for at least 6 weeks after delivery.

People can breastfeed while taking warfarin or low-molecular-weight heparin, but it is not clear if newer oral blood thinners are safe while nursing.

Symptoms of DVT may occur in the legs or arms and include:

  • swelling in the affected area
  • pain or tenderness that is not due to injury
  • increased warmth in the area
  • red or discolored skin

Vs. muscle cramps

Leg cramps can occur in pregnancy, commonly during the second and third trimester of pregnancy, and at night.

If leg pain does not go away, or the area is warm, swollen, red, or discolored, people should contact a doctor as it may be a sign of a blood clot.

Vs. pulmonary embolism

A PE occurs if a blood clot breaks free and travels to the lungs. A PE can be a life threatening condition and requires immediate medical care.

Symptoms of PE include:

  • difficulty breathing
  • chest pains, which worsen with coughing or deep breathing
  • increased or irregular heartbeat
  • coughing up blood

Doctors commonly prescribe oral blood thinners to treat DVT but many are not safe for a fetus.

Instead, treatment during pregnancy may include blood thinning medication injections under the skin, such as low-molecular-weight heparin.

These injections do not enter the bloodstream of a fetus or cross the placenta, so they are safe to take during pregnancy.

A doctor will deliver the injection into the abdomen, but this cannot harm a fetus, as the needle only reaches the top layers of skin.

Managing DVT during pregnancy may include:

  • having blood thinning medication injections, which are safe for the pregnant person and fetus
  • using compression devices, such as wearing compression stockings, to help promote healthy blood flow

These methods are safe and effective in helping prevent blood clots during and after pregnancy in people at high risk.

People can talk with a healthcare professional about the risks of blood clots during pregnancy and if they have any personal risk factors.

Steps to help prevent blood clots include:

  • avoid sitting for long periods and move around or stretch the legs every 1–2 hours if sitting down
  • stay well-hydrated and drink 10 glasses of fluid daily during pregnancy, and 12–13 glasses daily while nursing
  • take any medications or wear any compression devices, as a doctor prescribes

To diagnose DVT during pregnancy, a doctor may use imaging tests, such as an MRI scan and ultrasound.

A doctor will also use tests to check the health of the fetus by monitoring the heart rate and oxygen levels.

Blood clots can increase the risk of severe complications in pregnancy, but with proper management, people at risk are still able to have safe pregnancies and deliveries.

Heparin and low-molecular-weight heparin may help prevent blood clots and are safe to use during pregnancy without causing adverse side effects to a fetus.

The following are frequently asked questions about DVT.

Is DVT more likely to affect one leg more than the other?

DVT usually only occurs in one leg and may be more likely to affect the left leg than the right. A PE may occur more frequently with a right-sided DVT than a left-sided DVT.

Is it safe for people to conceive if they have DVT?

Most people with a blood clotting condition can still have healthy pregnancies. It is important to talk through potential risks with a healthcare professional and follow any treatment a doctor prescribes.

The risk of deep vein thrombosis increases with pregnancy and delivery, as well as in the months following childbirth.

People can discuss risk factors with a doctor and take steps to prevent blood clots. People may need blood thinning injections during pregnancy to manage DVT.