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Deep vein thrombosis (DVT) in pregnancy

Symptoms of DVT include swelling and pain in the lower legA deep vein thrombosis (DVT) happens when a blood clot forms in a vein.

DVTs usually happen in your calf or thigh, though they can happen in other large veins. The clot can sometimes break off and travel to your lungs, causing a very serious condition called pulmonary embolism (PE).

You're more at risk of having a DVT while you're pregnant and for six weeks after your baby is born.

If you have other risk factors, your chances of a DVT are even higher.

Other risk factors include:


Symptoms of a DVT


Because DVT can be serious, if you're experiencing any symptoms of a DVT, see your GP as soon as possible.

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 to your lungs.

Symptoms of PE can include:


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 help – call an ambulance on 111.

Diagnosing DVT and PE

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).

Treating DVT and PE

DVT is treated with anticoagulant (blood thinning) medicines that reduce your blood's ability to clot. This stops the DVT getting bigger and breaking loose.

You'll also need anticoagulants if you have a PE. If you have a severe PE, you may be given a medicine to dissolve the clot (a thrombolytic).

Your doctor will choose the most suitable type of anticoagulant for you.

Some people have ongoing problems after a DVT such as leg pain, swelling and rash. This is known as post-thrombotic syndrome. Your doctor may recommend you wear compression stockings if this happens.

If you've had a DVT, you'll need medication to stop more blood clots forming. Low dose enoxaparin (a form of heparin) is used for this during pregnancy. It's injected just under your skin.

Preventing DVT and PE

Things that can help prevent DVT and PE include:

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

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.

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Written by HealthInfo clinical advisers. Last reviewed December 2021.


Page reference: 100379

Review key: HIHCP-311277