This page is a layman’s terms summary of Antiphospholipid Syndrome (APS).  It covers such topics as diagnosis, symptoms, treatment, and coping.  It is meant for patients newly diagnosed, however would also be good for informing friends and family about your disease.

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What is Antiphospholipid Syndrome?

Antiphospholipid Syndrome or APS is an autoimmune disorder in which the body recognizes certain normal components of blood and/or cell membranes as foreign substances and produces antibodies against them. Patients with these antibodies may experience blood clots, including heart attacks and strokes, and miscarriages. APS may occur in people with systemic lupus erythematosus, other autoimmune diseases, or in otherwise healthy individuals.

APS is formerly known as APLS, APLA, Hughes Syndrome or “Sticky Blood.”

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APS is an Autoimmune Disease

One way in which our immune system fights infections is by making antibodies. Antibodies are proteins in the blood and body fluids that bind to foreign invaders like bacteria and viruses and help the immune system destroy and remove them. Sometimes the immune system doesn’t function properly and makes antibodies against normal organs and tissues in the body. These self-reactive antibodies are called autoantibodies. The autoantibodies in APS were originally thought to recognize that recognize certain phospholipids, fatty molecules that make up part of normal cell membranes, hence the name “antiphospholipid” antibodies. It is now known that most of the autoantibodies in APS patients actually recognize certain blood proteins that bind to phospholipids, not the phospholipids themselves. Two blood proteins that are major targets of antiphospholipid antibodies are 2-glycoprotein I and prothrombin.

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APS: The Statistics

  • Number 1 cause of stroke in young people.
  • 20% of all cases of blood clots in large veins (deep vein thrombosis), including blood clots that go to the lungs (pulmonary embolism) are due to APS.
  • 1 out of 5 women with recurrent miscarriages have APS.
  • One third of strokes occurring in younger people (under the age of 50) are due to APS.
  • APS is a major women’s health issue: 75-90% of those affected by APS are women.
  • 40-50% of patients with lupus also have APS.
  • Antiphospholipid Syndrome affects nine women for every man.
  • Estimated, as of 2019, to affect 1 in 2000 Americans.

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Clinical Features of APS

People with antiphospholipid antibodies have an increased risk of developing one or more of the following problems:

  • Blood clots in veins, particularly deep vein thrombosis (DVT)
  • Blood clots that go to the lungs (pulmonary embolism)
  • Blood clots in arteries
  • Miscarriages—these can occur at any stage of pregnancy but are most common in the late first trimester or early second trimester
  • Pre-eclampsia, eclampsia, fetal growth retardation, premature delivery
  • Heart attacks, angina
  • Strokes
  • Brief stroke-like episodes called transient ischemic attacks (TIAs), for example, loss of vision
  • Decreased levels of platelets (small blood cells involved in blood clotting)
  • Heart valve problems, sometimes requiring valve surgery or valve replacement
  • Persistent or transient blotchy, lacy bluish rash (livedo reticularis)
  • Skin ulcers, most commonly on the legs or feet
  • “Catastrophic” APS—a very rare, life-threatening syndrome in which clots form in small blood vessels of multiple organs (such as heart, lungs, brain, kidneys)

Other features that might be associated with antiphospholipid antibodies include:

  • Problems with thinking clearly (loss of concentration, difficulty with reading comprehension and performing calculations, memory loss)
  • Neurological problems similar to multiple sclerosis.
  • Migraine headaches, sometimes with visual disturbances
  • Other neurological symptoms including episodes of partial or total vision loss, dizziness, vertigo, loss of balance, seizures, and other abnormal movements

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How is APS Diagnosed?

Physicians use a combination of clinical symptoms (see above) and laboratory tests to diagnose APS. The common blood tests for antiphospholipid antibodies are as follows:

  • Anticardiolipin antibodies (IgG, IgM, and IgA)
  • Lupus anticoagulant—a panel of blood clotting tests that may include the dilute Russel Viper venom time (dRVVT), lupus aPTT, mixing studies, and hex phase phospholipid test, platelet neutralization procedure
  • Antibodies to b2-glycoprotein I (IgG, IgM, IgA)

Panels of tests for antibodies to phospholipids other than cardiolipin are available but have not undergone the rigorous international standardization efforts applied to anticardiolipin assays.  A number of experts in the field question the usefulness of these panels, which may be quite expensive.

If you test positive for any of the above tests, testing will be done 12 weeks later to confirm your diagnosis.

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APS Treatment and Prevention

There is no cure for APS, but there is treatment.  The treatment of choice for patients with APS who have had a blood clot is anticoagulant therapy.  This is usually successful in preventing further clots.  For women with APS and recurrent miscarriages who have not had a prior blood clot, the use of anticoagulant therapy during the pregnancy significantly increases the likelihood of a successful outcome.  Some individuals may have elevated antiphospholipid antibodies but have no clinical manifestations of the syndrome.  These individuals are usually treated with aspirin.  Aspirin reduces the risk of blood clots by making the platelets less sticky.  Studies are ongoing to determine how helpful aspirin is and whether low doses of anticoagulants might be more effective.

In general patients who have had a blood clot (i.e., stroke, heart attack, DVT) and have persistently positive tests for antiphospholipid antibodies should be treated with anticoagulants indefinitely.  Discontinuing treatment after a fixed period of time, such as six months, may be quite dangerous in such patients.  In some patients with a history of blood clots, antiphospholipid antibodies may disappear after a certain period of time.  It is not known whether it is safe to stop anticoagulation in this situation.  Consultation with a doctor experienced in treating APS is recommended for such patients.

The treatment of at risk patients may not always include anticoagulants but may include dietary changes, behavior modification, and/or treatment of associated conditions. Do not smoke or do drugs; drink plenty of water, watch your weight, and exercise, if possible.

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Doctors and Information on APS

Although APS is actually one of the more common autoimmune diseases, some primary care doctors remain uniformed about it. When their patients have symptoms of APS, these doctors may not test for antiphospholipid antibodies soon enough or at all. Unfortunately, many patients have had to see several physicians and specialists before getting the proper diagnosis and treatment.

The type of doctor a patient sees should be determined by the symptoms the individual patient is having, and any given patient may benefit from the input of several specialists. For patients with blood clots, a hematologist would be involved, often for management of anticoagulant therapy (blood thinner). For patients with recurrent miscarriages, a high-risk obstetrician should be consulted. For patients who also have rheumatologic symptoms, such as symptoms of lupus, a rheumatologist would be important to see. Of course, all patients would benefit from having a single physician identified as their primary care provider, to help coordinate all of their health care needs.

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Women & APS

APS and Pregnancy Complications

Women with APS may have difficulties with pregnancy. During pregnancy, women are at higher risk of developing blood clots and preeclampsia.  In APS, pregnancies are thought to be lost because blood clots form in the placenta and starve the baby of nutrition.  Some women may have trouble getting pregnant, while others may experience repeated miscarriages. Blood clots that develop in the placenta can cause fetal growth problems, fetal distress, preterm birth, or pregnancy loss.

Expert care and close monitoring of the pregnancy is essential by a doctor knowledgeable about APS.  During pregnancy, physicians may recommend low doses of aspirin and daily injections of the blood thinning drug, heparin.  This gives the fetus about an 80% chance of survival, a drastic improvement from the 1980’s when fetal survival was around 20%. The therapy is started at the beginning of pregnancy and halted just before delivery to reduce the risk of bleeding during childbirth. Soon after birth, the treatment resumes for about six weeks because of an increased risk for clotting in the postpartum period. In a more serious case preeclampsia may set in towards the end of pregnancy and a planned premature birth may be necessary.  Heparin can cause bone loss, so women may need to take additional calcium during pregnancy. In addition, women need to be monitored for development of a low platelet count.

Over the long term, many doctors recommend women continue to take a low dose of aspirin to reduce the risk of developing dangerous blood clots.  Many women with APS are unaware they have the condition, but it can be diagnosed with a blood test. Doctors may consider the diagnosis when a woman has repeated, unexplained pregnancy loss.

If you are trying to get pregnant or are pregnant it is very important to let your doctor know immediately. Continued use of warfarin may cause birth defects. The doctor will change your medication to a different blood thinner that is safe. Using proper treatment, women with APS have about the same risks as other women during pregnancy.

APS pregnancies are not normal. Normal pregnancy is 40 weeks. In APS, it is more common to deliver the baby between 30-35 weeks, and between 3-5 pounds. Heparin protects the placenta partially, but not fully so that the baby gets enough nutrition to survive longer in the mother. Once born, the babies do fine.

Many women who have problems with APS during pregnancy are completely fine when not pregnant. Others do go on to develop problems with clotting.  Currently there is no way of telling which women will be unlucky, until a clot actually occurs.

Infertility has also been linked to antiphospholipid antibodies. Testing for these antibodies is becoming routine in infertility clinics.

Birth Control Pills & Hormone Replacement Therapy

Women also need to avoid estrogen therapy (such as birth control or hormone replacement therapy) because estrogen predisposes patients to clotting.

Other forms of contraception should be discussed with your doctor.

Problems with Periods

Some women taking warfarin experience problems with increased bleeding. It can lead to anemia.  Tell your doctor about this problem. The doctor can recommend several options and prevent anemia. One example is: for women who have already given birth and are not actively trying to conceive, the Mirena® IUD has been successful in reducing period blood loss. As it only releases hormones to the uterus lining and is not absorbed into the blood stream, therefore, it is safe for women with APS to use.

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Other Points to Consider

You may notice you bruise more easily or little cuts will bleed longer when you are taking anticoagulants. Injuries can be more serious when on anticoagulants and care should be taken during any activity that can result in injury. Contact sports are not recommended.

If, while on anticoagulants, you injure your head, go directly to the Emergency Room. Your brain is very sensitive to a bleeding while on anticoagulants. If a serious injury does occur go directly to the Emergency Room and be sure they know you are taking anticoagulants and tell them what your most recent INR was, if on warfarin.

You should have Medical Alert bracelet and wear it at all times. You can order one through Medic Alert. A bracelet is the most visible, the easiest and the most recognized however, there are also necklaces and other types available.

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Safety When Traveling

Long trips, especially by air, have some clotting risk even for non-APS people. It is important for people with APS to get up and walk around at least every couple of hours. On long car trip stop at least every two hours and walk. Drink plenty of water and wear compression stockings to help reduce your chance of DVT. If you plan to be away during the time of a periodic blood test, arrange for the blood test before you leave for the trip.

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Take Your Medication

It is very important to take your medicine every day. Try to take your the medicine at the same time each day for consistency. You may want to get a pillbox that holds at least one week’s supply of the pill(s) or to mark it on a calendar when you take your medicine. This will help you to know when you have taken your pills. Do not take two doses in one day if you have forgotten your dose.

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Symptoms to Watch For

If you test positive for APS Antibodies you should be aware of the symptoms caused by blood clots. If any of these symptoms occur, seek medical help immediately.  Symptoms that could be caused by a blood clot include:

Heart Attack

Chest discomfort or pain. Most heart attacks involve discomfort in the center of the chest that lasts more than a few minutes, or that goes away and comes back. It can feel like uncomfortable pressure, squeezing, fullness or pain. Generally becomes so bad that it may feel unbearable and relentless, but occasionally the pain can be milder.

  • Discomfort in other areas of the upper body. Symptoms can include pain or discomfort in one or both arms, the back, neck, jaw or stomach.
  • Shortness of breath. This feeling often comes along with chest discomfort. But it can occur before the chest discomfort.
  • Other signs may include breaking out in a cold sweat, nausea or light-headedness.

Strokes (Blood Clot in the brain) can be life threatening. Some stroke symptoms may last only minutes or a few hours and are called TIA’s. (Transient Ischemic Attack or mini stroke.) Rapid treatment (within three hours) is vital.  Medical treatments that reverse the stroke damage is available—but only if you seek immediate treatment.  Stroke symptoms are:

  • Sudden numbness or weakness of the face, arm or leg, especially on one side of the body.
  • Sudden confusion, trouble speaking or understanding speech.
  • Sudden trouble seeing in one or both eyes.
  • Sudden trouble walking, dizziness, loss of balance or coordination.
  • Sudden, very severe headache with no known cause. Can also be very severe headache that lasts for days.
Clots in other locations

Muscle pain, numbness, or tingling, pale color, weakness, muscle spasm in a leg or arm.

  • The arm or leg feels cold, hot or swollen to touch.  May feel like a muscle strain.
  • Extreme pain without a cause, anywhere in the body.
  • Shortness of breath, or chest pain (under the breast bone or on one side of the chest) may radiate outward from the chest. (This could indicate a clot in the lungs or a heart attack.)
  • Sudden heavy cough especially if you cough up blood.
  • Rapid breathing.

Heart attacks, strokes and other blood clots need immediate medical attention. Go immediately to Emergency Room.

If you feel these warning signs, DIAL 911 IMMEDIATELY. Most people wait 2 or 3 hours before seeking care, yet by then the heart may suffer significant damage. Dial 911 within 5 minutes if you or someone you are with experiences these symptoms.

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Coping with APS

APS treatment is life long. Treatment of blood clots caused by APS outweighs the small side effects by treatment.
Most of the time people with APS will appear on the outside just as they did before they were diagnosed. Because of this, it may be difficult for family and friends to understand that you have a life threatening illness and that you just can’t do some of the things that you could before. They can’t see what is going on with your body and this can become quite frustrating on both ends.

In some cases you may want a therapist to help you adjust. Any person with a life threatening disease is at risk of being depressed. In some cases this progresses to clinical depression. It is very important to discuss your mental health with your doctor as well as your physical health.

The APS Foundation of America, Inc has a place on the Internet where you can communicate with others who have this disease. Find our support forum here . You are the only one who knows exactly how you feel. Others with the same disease are very understanding and support groups of some kind can make your life much fuller. Your immediate family and children should be told about your disease, how it affects you, what it means to them as well as what you may have to expect of them in support.

The good news is: many people with proper treatment live normal full lives. Others may find their lives changed forever due to APS, but a positive attitude will mean that life can still be worthwhile and fulfilling as the correct treatment prevents further problem.

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How Can You Help?

There are many ways you can help the APS Foundation of America, Inc.  You can volunteer your time & talents such as in the area of fundraising, advocacy, finance or support group experiences, donate money or purchase APS gear through our webpage, our CafePress store or our Zazzle store. We also have a Gift Shop on Facebook, where 100% of the profits from its products go to the APSFA.

The APS Foundation of America, Inc is a non-profit organization. 

Without your generous donations, the APSFA could not continue to provide APS patients and their families with the information on our foundation page and social media pages, support Antiphospholipid Syndrome (APS) research – both adult and pediatric, obtain education on APS and related disease through various mediums and share that with the APS community and the general community as a whole.  In addition, we are developing a strategic plan for the future course of the APSFA and plan to raise money towards our long term goals.

Thank you in advance for your support and time.  Please contact us through our website or call 608-782-2626 for more information.

Please send donations to:

APS Foundation of America, Inc
Post Office Box 801
La Crosse, Wisconsin 54602-0801

We also accept PayPal donations via our website.

We thank you for your support!

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APS Foundation of America, Inc. is not intended to replace standard doctor-patient visits, physical examination, and medical testing. Information given to members is only an opinion. All information should be confirmed with your personal doctor. Always seek the advice of a trained physician in person before seeking any new treatment regarding your medical diagnosis or condition. Any information received from APS Foundation of America, Inc is not intended to diagnose, treat, or cure. This brochure is for informational purposes only.

If you think you may have a medical emergency, call your doctor or 911 immediately.

A team of people contributed to this publication. Information was adapted from various website, books and other media sources.  Please contact us through the website for a complete list of sources.  This pamphlet was assessed at draft stage by doctors, allied health professionals, an education specialist and people with APS. A non-medical editor rewrote the text to make it easy to understand and an APS Foundation of America, Inc. medical editor is responsible for the content overall.

©Copyright 2005-2021 All rights reserved. All content in this pamphlet is protected by U.S. and international copyright laws and may not be reprinted, reposted, or otherwise reproduced wholly or in part without prior written permission from the APS Foundation of America, Inc. Bibliography available here.

Our Mission

Founded in 2005, the APS Foundation of America, Inc. is dedicated to fostering and facilitating joint efforts in the areas of education, public awareness, research, and patient services for Antiphospholipid Syndrome (APS) in an effective and ethical manner.


APS Foundation of America, Inc.
P. O. Box 801
LaCrosse, WI 54602-0801

DISCLAIMER: APS Foundation of America, Inc. website is not intended to replace standard doctor-patient visits, physical examination, and medical testing. Information given to members is only an opinion. All information should be confirmed with your personal doctor. Always seek the advice of a trained physician in person before seeking any new treatment regarding your medical diagnosis or condition. Any information received from APS Foundation of America, Inc. website is not intended to diagnose, treat, or cure. This site is for informational purposes only. Please note that we will be listing all donor or purchaser's names on the Donor page of our foundation site. If you do not want your name listed, please contact us to opt out. If you think you may have a medical emergency, call your doctor or 911 immediately.