Deep vein thrombosis (DVT) is a serious condition where blood clots develop, often in the deep veins of the legs (occasionally it can develop in the pelvis). It can be fatal if the clot travels from the legs to the lungs. Pregnant women are more likely to develop thrombosis than non-pregnant women of the same age. A clot can form at any stage of pregnancy and up to six weeks after the birth.
Other factors that put you at risk of thrombosis include:
- having had thrombosis (a clot) before
- being over 35
- having thrombophilia (a condition that makes clots more likely)
- being overweight
- carrying twins or more
- having just had a caesarean section
- sitting still for long periods of time, including on flights of more than five hours
- being a smoker (get support to stop smoking)
What are the symptoms of DVT?
The symptoms of DVT usually, but not always, occur in one leg only. Seek advice from your midwife or doctor immediately if you notice one or more of the following symptoms in your leg:
- swelling
- pain
- warm skin
- tenderness
- redness, particularly at the back of the leg below the knee
During pregnancy it's common to experience swelling or discomfort in your legs, so this doesn't mean there's a serious problem. If you're worried, talk to your midwife or GP.
A pulmonary embolism (PE) is when a blood clot travels to the lungs. It can be fatal. Symptoms of PE include:
- sudden difficulty in breathing
- chest pain or tightness
- in some cases, collapse
Once a DVT is diagnosed and treatment is started, the risk of developing a PE is very small.
Managing DVT in pregnancy
Injections with low molecular weight heparin are usually used to treat pregnant women with DVT. Low molecular weight heparin is an anticoagulant (meaning that it prevents the blood clot from getting bigger). It does not affect your developing baby. You can read general information about treating DVT in the Health A-Z section of this site.
Heparin prevents the clot getting bigger so that your body can dissolve it. The injections also reduce the risk of a pulmonary embolism and the risk of developing another clot in your leg.
Treatment usually lasts for the rest of your pregnancy and until at least six weeks after the birth. If necessary, it may continue for longer in order to complete a minimum of three months total treatment time.
Although medical treatment for DVT is essential, there are things you can do to help yourself, including:
- staying as active as you can – your midwife or doctor can advise you on this
- wearing a prescribed compression stocking to help the circulation in your leg
Travel
To reduce the risk of DVT while you're travelling:
- drink plenty of water
- don't drink alcohol, as it can lead to dehydration
- perform simple leg exercises, such as regularly flexing your ankles – most airlines provide information on suitable exercises to do during your flight
- take occasional short walks when in-flight advice says that it's safe to do so
- get off the plane during refuelling stopovers if possible, and walk about
Find out more about deep vein thrombosis (DVT).
