What is it?

Phospholipids are present in the membranes that form the surface of cells, including blood cells and endothelial cells that line blood vessels. In some people, the immune system develops antibodies to proteins that are attached to phospholipids. The presence of these antiphospholipid antibodies may increase the risk of developing blood clots in the veins or arteries and may cause an increased risk of miscarriage or stillbirth among pregnant women. However, some people have these antibodies and do not develop clots or have miscarriages.
People who have these antibodies and develop blood clots or pregnancy-related complications are said to have a syndrome called the antiphospholipid syndrome (APS). This is an autoimmune disorder, meaning that it occurs when the body's immune system mistakenly attacks healthy tissues and organs.
APS is more common in patients with other autoimmune or rheumatic diseases, particularly systemic lupus erythematosus (SLE).

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Additional names

This group contains additional names:
- Antiphospholipid Antibody Syndrome (APLS)
- Lupus Anticoagulant Syndrome
- Primary Hypercoagulable State

Signs & symptoms

Signs and symptoms of antiphospholipid syndrome may include:
- Blood clots in your legs (DVT). Signs of a DVT include pain, swelling and redness. These clots can travel to your lungs (pulmonary embolism).
- Repeated miscarriages or stillbirths. Other complications of pregnancy include dangerously high blood pressure (preeclampsia) and premature delivery.
- Stroke. A stroke can occur in a young person who has antiphospholipid syndrome but no known risk factors for cardiovascular diseases.
- Transient ischemic attack (TIA). Similar to a stroke, a TIA usually lasts only a few minutes and causes no permanent damage.
- Rash. Some people develop a red rash with a lacy, net-like pattern.


A diagnosis of antiphospholipid syndrome (APS) is based upon a patient's history and laboratory findings. The diagnosis requires the following:
- An episode of blood clots, one or more miscarriages after the 10th week of pregnancy, three or more miscarriages prior to the 10th week of pregnancy, or one or more premature births prior to the 34th week of pregnancy due to eclampsia.
- Antiphospholipid antibodies detected with blood testing on at least two different occasions at least 12 weeks apart. Antiphospholipid antibody tests include the lupus anticoagulant, anti-cardiolipin antibodies, and anti-beta-2-glycoprotein I antibodies.


If you have blood clots, standard initial treatment involves a combination of blood-thinning medications. The most common are heparin and warfarin (Coumadin, Jantoven). Heparin is fast-acting and delivered via injections. Warfarin comes in pill form and takes several days to take effect. Aspirin is also a blood thinner.

☝️ This is not a substitute for professional medical advice. Please consult with your physician before making any medical decision.

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