HealthInfo West Coast-Te Tai Poutini
A 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 a pulmonary embolism (PE).
You are more at risk of having a DVT while you are pregnant and for 6 weeks after your baby is born.
If you have other risk factors, your chances of a DVT are even higher.
Other risk factors include:
A DVT can cause a life-threatening complication called a pulmonary embolism (PE). This is when part or all of a clot breaks off and travels to your lungs.
Symptoms of a PE can include:
A DVT can be serious. If you are experiencing any symptoms of a DVT, see your general practice team as soon as possible.
A PE is very serious. If you have any of the symptoms of a PE, especially if you have one or more risk factors, get immediate medical help. Call an ambulance on 111.
A DVT is generally diagnosed using venous doppler ultrasound, which uses sound waves to check the flow of blood in your veins.
A PE is diagnosed in 1 of 2 ways. The first is a CT scan of your lung (a special type of X-ray that shows pictures of structures inside your body). The second is a ventilation-perfusion lung scan (a special test that shows how much blood is getting into your lungs).
A 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 will 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 have had a DVT, you will need medication to stop more blood clots forming. Low dose enoxaparin (a form of heparin) is used for this during pregnancy. It is injected just under your skin.
Things that can help prevent DVTs and PEs include:
When you are sitting or lying for long periods, or when you are travelling for more than 6 hours:
After a clot, always tell future health caregivers that you have had a blood clot, DVT or PE. This information is important in planning your future care, including in a later pregnancy.
HealthInfo recommends the following pages
Information about DVT. Includes detailed information about symptoms, causes, diagnosis and treatment.
Detailed information about pulmonary embolism, including causes, symptoms, treatment and prevention.
Written by HealthInfo clinical advisers. Last reviewed November 2024.
Review key: HIHCP-311277