Antiphospholipid syndrome (APS)

What is APS?

Antiphospholipid syndrome (APS), also known as ‘sticky blood syndrome’, is a condition that causes blood clotting in your arteries or veins and is also a major cause of recurrent miscarriage. It can occur on its own or alongside lupus.

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What are the symptoms of APS?

The two main symptoms are blood clotting and pregnancy problems, particularly recurrent miscarriage. Blood clotting can occur in your:

• veins
• arteries
• brain

In pregnancy, APS can cause recurrent miscarriage and other pregnancy problems such as high blood pressure (pre-eclampsia), small babies and early deliveries.

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What causes APS?

If you have APS, your immune system produces harmful antibodies called antiphospholipid antibodies (aPL). These aPL antibodies affect cells in your blood and in the walls of your blood vessels in such a way that your blood becomes ‘sticky’ and more likely to clot inside the vessels. Clotting inside vessels is called thrombosis.

If you’re pregnant, aPL can also affect your womb and the placenta in a way that can make your baby grow more slowly and increase your risk of miscarriage.

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How is APS diagnosed?

Your diagnosis will be made from the clinical history of blood clots and/or pregnancy loss, confirmed with one or more of three particular blood tests:

• the anticardiolipin test
• the lupus anticoagulant test
• the anti-beta-2-glycoprotein I test

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What treatments are there for APS?

You’ll probably be treated with drugs that thin your blood:

• If you carry the antiphospholipid antibodies but have no history of clotting, you’ll probably be given low-dose aspirin.
• If you have APS and a history of clotting, you’ll probably be given warfarin to prevent further clots.
• If you’ve had a number of miscarriages, but no history of clotting, you’ll probably be given low-dose aspirin during pregnancy to prevent another miscarriage – you may be given injections of heparin as well. After giving birth you may be advised to continue low-dose aspirin to prevent clotting.
• If you’ve suffered both miscarriages and clotting you’ll probably be given warfarin when you’re not pregnant, but this will be changed to heparin when you’re pregnant and aspirin will be added.

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Self-help and daily living

You can help yourself by:

• exercising
• eating a healthy, balanced diet
• not smoking
• thinking ahead if you're going to have to keep still for a long time (e.g. on a long-haul flight)

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