Treating antiphospholipid syndrome (APS) 

There is no cure for antiphospholipid syndrome (APS), so treatment aims to reduce your risk of developing more blood clots.


As part of your treatment, you will be prescribed anticoagulant medicines such as warfarin or an antiplatelet medication such as low-dose aspirin.

These work by interrupting the process of blood clot formation. This means that blood clots are less likely to form when they are not needed, but they will still form when they are needed, for example when you cut yourself.

Your treatment plan

Most people with APS will need to take anticoagulant or antiplatelet medication daily for the rest of their life.

If blood tests show that you have abnormal antiphospholipid antibodies but you do not have a history of blood clots, low-dose aspirin tablets are usually the first treatment recommended. If you cannot take aspirin, you may be prescribed an alternative antiplatelet tablet called clopidogrel.

Warfarin tablets are usually recommended if you have APS and a history of blood clots, such as previously having deep vein thrombosis (DVT) or a stroke. However, this will need to be changed if you become pregnant or are planning a pregnancy (see below), so you should tell your doctor if this is the case.

If you develop a blood clot or your symptoms suddenly become severe, injections of an anticoagulant called heparin may be needed. These injections may be given in hospital, or you may be trained to give them yourself.

Side effects

Side effects of these medications are uncommon and generally mild, such as indigestion or feeling sick (nausea).

However, there is a risk that the disruption to the blood’s ability to clot can cause excessive bleeding (a haemorrhage).

Symptoms of excessive bleeding can include:

  • blood in your urine or faeces
  • black faeces
  • severe bruising
  • prolonged nosebleeds (lasting longer than 10 minutes)
  • blood in your vomit
  • coughing up blood

Contact your GP immediately if you have any of these symptoms while taking an anticoagulant. If this is not possible, call your local out-of-hours service or NHS 111.

Treatment during pregnancy

Women who are diagnosed with APS are strongly advised to plan for any future pregnancy. This is because treatment to improve the outcome of a pregnancy is most effective when it begins as soon as possible after an attempt to conceive and some medications used to treat APS can harm an unborn baby.

If you do not plan your pregnancy, it may be several weeks before you realise you are pregnant, which may increase the risk of treatment to safeguard the pregnancy being unsuccessful.

Treatment during pregnancy involves taking daily doses of aspirin or heparin, or a combination of both, depending on whether you have a history of blood clots and previous complications during pregnancy. Warfarin is not recommended during pregnancy because it carries a small risk of causing birth defects.

Treatment with aspirin and/or heparin is usually started at the beginning of the pregnancy and may continue for one to six weeks after you have given birth.

Lifestyle changes

If you are diagnosed with APS, it is important that you take all possible steps to reduce your risk of developing blood clots. Effective ways of achieving this include:

Page last reviewed: 06/11/2013

Next review due: 06/11/2015