• leg
  • thigh
  • pelvis
at least 5 times more likely


The most obvious symptom of DVT is swelling and heavy pain or extreme tenderness in one of your legs. Up to 90 percent of DVT cases in pregnancy occur in the left leg. Other symptoms of DVT include:
  • pain in the leg when standing or moving around
  • pain in the leg that worsens when you bend your foot up toward your knee
  • warm skin in the affected area
  • red skin at the back of the leg, typically below the knee
  • slight to severe swelling

Is it a muscle cramp or a symptom of DVT?

Muscle cramps are common during pregnancy. They typically affect the calf, particularly at night during the second and third trimesters. They can be prevented with:
  • stretching
  • magnesium supplements
  • comfortable, supportive footwear
  • Stretching and moving around will not improve pain from DVT. Muscle cramps will not cause your leg to appear swollen.

Pulmonary embolism vs. DVT

Another type of blood clot is pulmonary embolism (PE), a blood clot in the lungs. PE is rare during pregnancy, but more common than in nonpregnant women. Symptoms of PE include:
  • sudden shortness of breath
  • chest pain or tightness in the chest
  • a cough that produces blood-streaked sputum
  • rapid heartbeat

When should you see a doctor?

See your healthcare provider as soon as possible if you suspect DVT. While it’s not a medical emergency and is unlikely to harm you or your baby unless there are serious complications, it’s best to get checked early.


It’s not always easy to diagnose DVT in pregnancy from symptoms alone. Your healthcare provider may recommend a blood test called a D-dimer test. A D-dimer test is used to identify pieces of blood clot that have broken off into your bloodstream. An ultrasound will also be carried out to confirm DVT, because blood clot fragments can increase during pregnancy. A Doppler ultrasound, which is a type of scan that can determine how fast the blood is flowing through a blood vessel, can help healthcare providers establish whether blood flow is slowed or blocked. Slowed or blocked blood flow can be a sign of a blood clot. If a D-dimer test and ultrasound cannot confirm a DVT diagnosis, your healthcare provider may use a venogram or magnetic resonance imaging (MRI). A venogram involves injecting a liquid called a contrast dye into a vein in your foot. The dye moves up the leg and can be picked up by X-ray, which pinpoints a gap in the blood vessel where the blood flow is stopped by a clot.


DVT is easy to treat during pregnancy. Your healthcare provider will refer you to a specialist. Specialists can include a hematologist (blood specialist), as well as a maternal medicine or obstetric medicine specialist. To treat the DVT, the blood-thinning agent low-molecular-weight heparin (LMWH) will be injected once or twice daily to:
  • stop the clot from getting bigger
  • help the clot dissolve in the body
  • reduce the risk for further clots
You’ll have regular checkups and blood tests to ensure the clot has dissolved and no further clots have appeared.

Effects on the baby

DVT during pregnancy does not affect the baby unless there are serious complications. Heparin is safe to use during pregnancy because it doesn’t cross the placenta, so there is no risk to your baby. Your pregnancy should continue as normal. The injections will be stopped as soon as you begin normal labor, or at least 12 to 24 hours before labor is induced or a planned cesarean delivery takes place, depending on the anticoagulation regimen you are on. If you want to breastfeed your baby, you will have to stop the injections after birth and take a tablet called warfarin (Coumadin) to ensure the baby’s blood doesn’t thin.

Other complications

Long-term DVT can lead to permanent swelling of the veins and fluid retention. In rare cases, the clot dislodges and moves to the lungs, resulting in a PE.

Risk factors

Factors that increase your risk for DVT during pregnancy are:
  • having a previous history of clots or DVT
  • having a family history of DVT
  • being over 35
  • having a BMI of 30 or more
  • carrying twins or multiple babies
  • having fertility treatment
  • having had a previous, recent cesarean delivery
  • sitting still for long periods of time
  • smoking
  • having overweight or obesity
  • having preeclampsia, or certain chronic illnesses such as high blood pressure (hypertension) and inflammatory bowel disease (IBD)
  • severe varicose veins


There isn’t a way to prevent DVT in pregnancy, but there are several steps you can take to reduce your risk:
  • Stay active with pregnancy-safe exercises.
  • Wear flight socks during air travel and walk around at least once every hour.
  • Move your legs when sitting down, for example by raising and lowering your heels and your toes, and flexing your ankle.
  • Wear support hose.
  • Quit smoking, if you smoke.
  • See your healthcare provider immediately if you notice any pain, tenderness, redness, or swelling in your legs.
Pregnant women at high risk for DVT may be given a preventive dose of heparin, either during the entire pregnancy or for 6 to 8 weeks postpartum.


DVT isn’t common in pregnancy, but it’s a serious condition that can be fatal if the clot dislodges and moves into the lungs. Be aware of the symptoms and risks factors. Let your healthcare provider know right away if you suspect DVT. Early treatment can help keep you and your baby safe.