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Deep vein thrombosis (DVT) in pregnancy

If you have an increased risk of blood clots (thrombosis) because of factors relating to you or your pregnancy, this information may help you.

What is DVT?

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 is 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 the risk are:

What are the symptoms and signs of DVT?

The following symptoms are the most common and usually happen in the affected arm or leg (limb):

Since the symptoms of DVT can be similar to other conditions, like a pulled muscle, diagnosis is often delayed. Some people with DVT may have no symptoms at all.

DVT and pulmonary embolism (PE)

DVT can cause a life-threatening complication called pulmonary embolism (PE). This means part or all of a clot has broken off and travelled through your bloodstream and into your lungs. A blood clot in the lungs can kill you.

Symptoms of PE can include:

If you have any of these symptoms, it is an emergency and you should seek medical help immediately.

What can I do to prevent DVT and PE? FDP woman walking

You can prevent most DVT and PE. In general:

When you are sitting or lying for long periods of time, or when you are 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 are having surgery, you may be given elastic stockings to wear.

If you are confined to bed, move around as soon as possible.

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. This is usually given as a small injection under your skin (subcutaneous layer), sometimes for several days until you are 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 the veins.

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

What is the treatment for DVT and PE?

Compression stockings, also called elastic stockings, are sometimes recommended to relieve pain and swelling after DVT. Anticoagulants are also used to treat PE.

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

In cases of severe PE, medicines (thrombolytics) may be given to dissolve the clot, followed by anticoagulants to prevent more clots from forming.

Anticoagulants include heparin as an injection, or tablets (often warfarin). The one prescribed for you depends on your condition.

After a clot, always tell future health caregivers that you have had a blood clot, DVT or PE in the past. 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. Updated December 2015.


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

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