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Antiphospholipid antibody syndrome is an autoimmune disorder (a disorder where your immune system attacks your own body's organs). Antiphospholipid antibody syndrome makes it more likely for blood clots to form in your blood vessels. These clots can form anywhere in the body, but most often form in the legs. A blood clot that forms in the brain can cause a stroke.This can also cause blood clots in the kidneys, lungs, and heart. In pregnany women, antiphospholipid syndrome also can result in pregnancy complications such as miscarriage and stillbirth. 

Antiphospholipid antibody syndrome is thought to be relatively common - it is estimated that 20% of people under 50 who have a stroke also have antiphospholipid antibody syndrome. Antiphospholipid antibody syndrome mainly affects females, who comprise up to 70% of people diagnosed with this syndrome.                                                                                


Antiphospholipid antibody syndrome often goes undiagnosed. It generally first appears in early to mid-adulthood but can begin at any age.

Below are some signs that can indicate antiphospholipid antibody syndrome:

  • Formation of a blood clot
  • Complication during pregnancy (recurrent miscarriages or stillbirth)
  • Reduced platelets in the blood stream (platelets are cells involved in clotting)
  • Reduced red blood cells (anaemia)
  • Purplish skin discolouration
  • Open sores on skin
  • Migraines
  • Heart disease
  • Intellectual disabilities
  • Other autoimmune disorders
* Read about Pia's journey of living with Antiphospholipid Antibody Syndrome (APS).


Antiphospholipid antibody syndrome is caused when your body produces one or more of the three types of  abnormal antibodies (proteins which normally help to protect your body). These antibodies (lupus anticoagulant, anti-cardiolipin, and anti-beta-2-glycoprotein-1) target and attack molecules called phospholipids – which are present on every cell in your body. When antibodies attack phospholipids, blood vessel walls can be damaged, and this can increase the amount of clotting in your blood.


Your doctor will diagnose antiphospholipid antibody syndrome based evaluating the signs and symptoms together with the blood investigation results which will include the lupus anticoagulant, anticardiolipin and anti-beta-2-glycoprotein-1. Some individuals may have the antibodies without any symptoms. These antibodies may also be transiently present in the event of an infection and does not necessarily indicate the presence of the disorder. You should discuss this with your doctor.


There is currently no cure for antiphospholipid antibody syndrome, but medication is available to help to prevent complications. This treatment is used to prevent the formation of blood clots. Research is ongoing to discover new treatments for this syndrome.

Common blood-thinning medication (also known as anticoagulants) may be prescribed including Warfarin, and heparin.    


Antiphospholipid antibody syndrome can increase the risk of complications during pregnancy. However, it is still possible for pregnant women with antiphospholipid antibody syndrome to have successful pregnancies. Pregnant women with this syndrome are usually treated with low-molecular-weight-heparin and low-dose aspirin rather than Warfarin, to avoid harmful side-effects to the foetus.

Talk to your doctor to discuss the risks and options relevant to you.                                                                              


To reduce the risk of developing dangerous blood clots that is associated with thrombophilias such as antiphospholipid antibody syndrome:

  • Exercise regularly:
    • Exercising helps to dissolve and prevent blood clots.
  • Keep moving:
    • Being still – sitting and lying down – for long periods of time can increase your risk of a blood clots.
  • Maintain a healthy weight:
    • Overweight and obese people have a higher risk of blood clots.
  • Quit smoking
    • Smoking increases your risk of thrombosis - seek medical advice on how you can successfully quit.
  • Seek medical advice before:
    • Major surgery – Blood vessels can be damaged during surgery which increases your risk of blood clots.
    • Contraceptive or hormone therapy use – Hormones in birth control and hormonal therapies can increase your risk of clotting.
    • Pregnancy - Thrombophilia can increase your chances of blood clots during pregnancy, as well as other complications.          


Antiphospholipid antibody syndrome is an autoimmune disease – what is that?

Your body’s immune system constantly produces antibodies to fight infection and keep you healthy. An autoimmune disease is a condition where your immune system produces antibodies that target your own body, causing disease.

What are antiphospholipid antibodies?

Phospholipids are proteins which are found throughout the body. Antiphospholipid antibodies target these phospholipids and can cause your blood to clot more easily, increasing your chances of thrombosis.

There are three antiphospholipid antibodies, known as: lupus anticoagulant, beta-2 glycoprotein I, and anti-cardiopilin.

How did I get these antibodies?

It is largely unknown how people get these antibodies. Sometimes these are the result of infections or existing conditions, and sometimes they seem to run in families.

What causes antiphospholipid syndrome?

The syndrome appears to be caused by the presence of the antiphospholipid antibodies. Why these antibodies are produced is largely unknown.

Is antiphospholipid syndrome infectious?

No, it is not a contagious disease.

Is antiphospholipid syndrome fatal?

People may have the antiphospholipid antibodies and be completely asymptomatic. However, the antibodies can very rarely be associated with a deadly variant of this condition called catastrophic antiphospholipid syndrome which occurs in less than 1% of patients. Antiphospholipid syndrome can also cause blood clots which can be fatal.  

Is antiphospholipid syndrome hereditary?

No. However, the presence of one or more of the antiphospholipid syndrome antibodies may run in the family. But this doesn’t necessarily indicate that your parents or children will also have the condition.

For an in-depth review of information about antiphospholipid antibody syndrome visit: Patient education: The antiphospholipid syndrome (Beyond the Basics).

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  • Mezhov, V., Segan, J., Tran, H., and Cicuttini, F. Antiphospholipid Syndrome: a clinical review. Med J Aust 2019; 211(4): 184-188.
  • National Heart, Lung, and Blood Institute:
  • Garcia D, Erkan D. Diagnosis and Management of the Antiphospholipid Syndrome. N Engl J Med. 2018 May 24;378(21):2010-2021. 
  • Chaturvedi S, McCrae KR. Diagnosis and management of the antiphospholipid syndrome. Blood Rev. 2017 Nov;31(6):406-417. [Medline]