Open a PDF version to print this topic

HealthInfo Canterbury

Deep vein thrombosis (DVT) in pregnancy

Deep vein thrombosis (DVT) happens when an abnormal blood clot forms in a large vein. These clots usually develop in the lower leg, thigh, or pelvis, but can also happen in other large veins. If you develop DVT and it's diagnosed correctly and quickly, it can be treated.

Can DVT happen to me?

Anyone may be at risk for DVT, but the more risk factors you have, the higher your chances are of developing DVT.

What are the risk factors?

FDP pregnant profileKnowing your risk factors can help you prevent DVT. Things that increase your risk are:

How do I know if I have a DVT?

If you have a DVT, you'll notice some or all of the following symptoms in your affected arm or leg (limb):

Since the symptoms of DVT can be similar to other conditions, like a pulled muscle or skin infection (cellulitis), it can be difficult to diagnose.

DVT and pulmonary embolism (PE)

DVT can cause a life-threatening complication called pulmonary embolism (PE). This is when part or all of a clot breaks off and travels into your lungs.

Symptoms of PE can include sudden shortness of breath, chest pain or discomfort (which gets worse when you breath deeply or cough), coughing up blood, and sudden collapse.


Because a pulmonary embolism is very serious, if you have any of the symptoms of a pulmonary embolism, especially if you have one or more risk factors, get immediate medical assistance – call an ambulance on 111.

What can I do to prevent DVT and PE?

FDP woman walkingThings that can help prevent DVT and PE include:

When you're sitting or lying for long periods of time, or when you're travelling for more than six hours:

Before and during hospitalisation

Talk to your healthcare provider about preventing blood clots and tell them if you have any risk factors for DVT.

If you're having surgery, you may be given elastic stockings to wear.

If you're confined to bed, move around as soon as you can.

After surgery, such as a caesarean section, or hospitalisation for a medical illness, you may be given a small dose of anticoagulant medication to prevent DVT and PE. You'll probably have this as a small injection under your skin (subcutaneous layer), sometimes for several days until you're mobile again.

How are DVT and PE diagnosed?

DVT is generally diagnosed using venous doppler ultrasound, which uses sound waves to check the flow of blood in your veins.

PE is diagnosed using a CT scan of your lung (a special type of X-ray that shows pictures of structures inside your body) or a ventilation-perfusion lung scan (a special test that shows how much blood is getting into your lungs).

How are DVT and PE treated?

Deep vein thrombosis and pulmonary embolism are treated with drugs that stop you from getting more blood clots. These are called anticoagulants. Doctors may also recommend you use compression stockings, also called elastic stockings, to relieve the pain and swelling after DVT.

You can buy a device at your local health and mobility shop to help you put your compression stockings on. This video shows you how to use one of these devices.

If you have severe PE, you may be given a medicine to dissolve the clot (a thrombolytic), followed by anticoagulants to prevent more clots from forming.

Anticoagulants include heparin, which is given as an injection, or tablets (often warfarin).

After a clot, always tell future health caregivers that you've had a blood clot, DVT or PE. This information is important in planning your future care, including in a later pregnancy.

Written by Quality and Safety Unit, Christchurch Women's Hospital. Adapted by HealthInfo clinical advisers. Last reviewed June 2018.


Images courtesy of Pregnant woman by imagerymajestic; woman walking by stockimages.

Page reference: 100379

Review key: HIHCP-311277