Antiphospholipid Syndrome

Antiphospholipid antibody syndrome (APS) is an autoimmune disease mostly affecting women between ages 30 and 40. In APS, abnormal proteins (aPL) can cause the formation of clots in veins and arteries. Clots may cause miscarriage, harm a fetus, or lead to heart attacks, strokes, or pulmonary embolism. In severe cases, multiple organs may be damaged. About 40% of systemic lupus erythematosus (SLE) patients also test positive for antiphospholipid antibodies, but only a few develop clots.

What Are the Signs/Symptoms?

APS may not be detected until an individual has unexpected problems caused by blood clots, such as repeated miscarriages or a heart attack. To screen people, three blood tests are checked and at least one must be positive and confirmed twice at least three months apart. Some people with these autoantibodies never develop clots; Risk factors for developing blood clots include high blood pressure, obesity, smoking, atherosclerosis, taking birth control pills, or having an associated autoimmune disease like SLE.

What Are the Common Treatments?

APS raises the risk for blood clots, so treatments aim to prevent clot-related events. In an acute event Initially intravenous blood thinners or subcutaneous (under the skin injections) blood thinners are followed by oral medications such as warfarin, which may prevent future clot Aspirin and clopidogrel (Plavix) may also prevent recurring clotting events. To help prevent a miscarriage, women with APS may be advised to use heparin low-dose aspirin, corticosteroids, or intravenous immunoglobulin during their pregnancies. Pregnant women with aPL autoantibodies who have never had thrombotic events or miscarriages may get preventive therapy.

Living with APS

Individuals who take blood thinners long term must see their healthcare provider regularly to monitor the drug. Lifestyle changes should be implemented to prevent clots such as managing weight and stop smoking, avoiding estrogen therapy for birth control or menopausal symptoms unless a physician directs.

Updated February 2023 by Mohammad Ursani, MD, and reviewed by the American College of Rheumatology Committee on Communications and Marketing.

This information is provided for general education only. Individuals should consult a qualified health care provider for professional medical advice, diagnosis and treatment of a medical or health condition.