Medically reviewed on February 9, 2017
Antiphospholipid (AN-te-fos-fo-LIP-id) syndrome occurs when your immune system attacks some of the normal proteins in your blood. It can cause blood clots in your arteries or veins. And it can cause pregnancy complications, such as miscarriage and stillbirth.
Blood clots in your leg veins cause a condition known as deep vein thrombosis (DVT). Damage from blood clots in your organs, such as your kidneys, lungs or brain, depends on the extent and location of the clot. For instance, a clot in your brain can cause a stroke.
There's no cure for antiphospholipid syndrome, but medications can reduce your risk of blood clots.
Signs and symptoms of antiphospholipid syndrome can include:
- Blood clots in your legs (DVT). The clots can travel to your lungs (pulmonary embolism).
- Repeated miscarriages or stillbirths. Other complications of pregnancy include premature delivery and high blood pressure during pregnancy (preeclampsia).
- Stroke. A stroke can occur in a young person who has antiphospholipid syndrome but no known risk factors for cardiovascular diseases.
- Transitory 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 (livedo reticularis).
Less common signs and symptoms include:
- Neurological symptoms. Chronic headaches, including migraines; dementia and seizures are possible when a blood clot blocks blood flow to parts of your brain.
- Cardiovascular disease. Antiphospholipid syndrome can damage heart valves.
Bleeding. Some people have a decrease in blood cells needed for clotting (platelets). If you have this condition (thrombocytopenia), you might have few or no symptoms.
However, if your platelet count drops too low, you might have episodes of bleeding, particularly from your nose and gums. You can also bleed into your skin, which will appear as patches of small red spots (petechiae).
When to see a doctor
If you have another autoimmune condition, talk to your doctor about whether you should be tested for antiphospholipid antibodies.
Other reasons to contact your doctor include:
- Pain, swelling, redness, or tenderness in your leg or arm. Seek emergency care if vein swelling and pain are severe or are accompanied by chest pain or shortness of breath.
Vaginal spotting or bleeding during pregnancy. This can be a sign of miscarriage or other pregnancy problems. However, many women who spot or bleed have a healthy pregnancy.
If you've had pregnancy losses or unexplained severe complications of pregnancy, talk to your doctor about getting tested.
If you have antiphospholipid syndrome and you're thinking about getting pregnant, ask your doctor what treatments are available during your pregnancy.
When it's an emergency
Seek emergency care if you have signs and symptoms of:
- Stroke. These include sudden numbness, weakness or paralysis of your face, arm or leg; difficulty speaking or understanding speech; visual disturbances; severe headache; and dizziness
- Pulmonary embolism. These include sudden shortness of breath, chest pain and coughing up blood-streaked mucus
- Deep vein thrombosis. These include leg swelling or pain
- Other bleeding. These include unexplained bleeding from your nose or gums; an unusually heavy menstrual period; vomit that is bright red or looks like coffee grounds; black, tarry stool or bright red stool; and unexplained abdominal pain
The role of phospholipids
In antiphospholipid syndrome, your blood clots abnormally because your body mistakenly produces antibodies that attack phospholipids, a type of fat that plays a key role in clotting. Antibodies are proteins that normally protect the body against invaders, such as viruses and bacteria.
You can have antiphospholipid antibodies, but you'll be diagnosed with the syndrome only if they cause health problems. Antiphospholipid syndrome can be caused by an underlying condition, such as an autoimmune disorder, infection or certain medications, or you can develop the syndrome without an underlying cause.
Antiphospholipid syndrome affects women much more than it does men. Other risk factors include:
- Having an autoimmune condition, such as systemic lupus erythematosus or Sjogren's syndrome
- Having certain infections, such as syphilis, HIV/AIDS, hepatitis C or Lyme disease
- Taking certain medications, such as hydralazine for high blood pressure, the heart rhythm-regulating medication quinidine, the anti-seizure medication phenytoin (Dilantin) and the antibiotic amoxicillin
- Having a family member with antiphospholipid syndrome
Risk factors for developing symptoms
It's possible to have the antibodies associated with antiphospholipid syndrome without developing signs or symptoms. However, having these antibodies increases your risk of developing blood clots, particularly if you:
- Become pregnant
- Are immobile for a time, such as being on bed rest or sitting during a long flight
- Have surgery
- Smoke cigarettes
- Take oral contraceptives or estrogen therapy for menopause
- Have high cholesterol and triglycerides levels
Depending on which organ is affected by a blood clot and how severe the obstruction of blood flow to that organ is, untreated antiphospholipid syndrome can lead to permanent organ damage or death. Complications include:
- Kidney failure. This can result from decreased blood flow to your kidneys.
- Stroke. Decreased blood flow to a part of your brain can cause a stroke, which can result in permanent neurological damage, such as partial paralysis and loss of speech (aphasia).
- Cardiovascular problems. A blood clot in your leg can damage the valves in the veins, which keep blood flowing to your heart. This can result in chronic swelling and discoloration in your lower legs (chronic venous insufficiency). Another possible complication is heart damage.
- Lung problems. These can include high blood pressure in your lungs (pulmonary hypertension) and pulmonary embolism.
- Pregnancy complications. These can include miscarriages, stillbirths, premature delivery, slow fetal growth and high blood pressure during pregnancy (preeclampsia).
Rarely, a person can have repeated clotting events in a short time, leading to progressive damage in multiple organs (catastrophic antiphospholipid syndrome).
If you have one or more episodes of thrombosis or pregnancy loss that aren't explained by known health conditions, your doctor can schedule blood tests to check for abnormal clotting and for the presence of antibodies to phospholipids.
To confirm a diagnosis of antiphospholipid syndrome, the antibodies must appear in your blood at least twice, in tests conducted 12 or more weeks apart.
Doctors generally use medications that reduce your blood's tendency to clot to help prevent complications of antiphospholipid syndrome.
Standard initial treatment
If you have thrombosis, standard initial treatment involves a combination of blood-thinning (anticoagulant) medications.
- Heparin. Typically, you'll first be given an injection of the blood thinner heparin, combined with another blood thinner in pill form, likely warfarin (Coumadin, Jantoven).
- Warfarin. After several days of combined heparin and warfarin, your doctor might discontinue the heparin and continue the warfarin, possibly for the rest of your life.
- Aspirin. In some cases, your doctor might recommend adding low-dose aspirin to your treatment plan.
When you're taking anticoagulant medication, you have an increased risk of bleeding episodes. Your doctor will monitor your dosage with blood tests to be sure your blood is capable of clotting enough to stop the bleeding of a cut or the bleeding under the skin from a bruise.
Treatment during pregnancy
During pregnancy, treatment to keep your blood from clotting increases your chances of carrying to term. Treatment includes:
- Heparin. Some forms of heparin — enoxaparin (Lovenox) and dalteparin (Fragmin) — are known as low-molecular-weight heparin, which you can inject yourself under your skin (subcutaneously). Heparin is considered safe to take during pregnancy.
- Aspirin. If you're pregnant, your doctor might recommend taking one tablet of aspirin daily in addition to the heparin, to increase your chances of a successful pregnancy.
Possible future treatments
Several new treatments are being considered for antiphospholipid syndrome, including:
- New blood thinners (anticoagulants). A number of oral blood thinners — dabigatran (Pradaxa), rivaroxaban (Xarelto) and apixaban (Eliquis) — have recently been approved to treat other conditions. It's not clear yet if these drugs are appropriate for treating antiphospholipid syndrome. None is recommended for use during pregnancy or breast-feeding.
- Rituximab (Rituxan). This drug has been used successfully to treat conditions affecting the immune system. But there isn't yet enough evidence of benefit to recommend rituximab as a treatment for antiphospholipid syndrome.
Lifestyle and home remedies
Depending on your treatment plan for antiphospholipid syndrome, there are additional steps you can take to protect your health.
If you take anticoagulants
Take extra care to keep from injuring yourself and to avoid bleeding.
- Avoid contact sports or other activities that could cause bruising or injury or cause you to fall.
- Use a soft toothbrush and waxed floss.
- Shave with an electric razor.
- Take extra care when using knives, scissors and other sharp tools.
Certain foods and medications may affect how well your anticoagulants work. Ask your doctor for guidance about:
Safe dietary choices. Vitamin K can lessen the effectiveness of warfarin, but not other anticoagulants. Eating small amounts of vitamin K-rich foods might not be harmful, but avoid eating large amounts of avocado, broccoli, Brussels sprouts, cabbage, leafy greens and garbanzo beans.
On the other hand, cranberry juice and alcohol can increase warfarin's blood-thinning effect. Ask your doctor if you need to limit or avoid these drinks.
- Safe medications and dietary supplements. Certain medications, vitamins and herbal products can interact dangerously with warfarin. These include some over-the-counter pain relievers, cold medicines, stomach remedies or multivitamins, as well as garlic, ginkgo and green tea products.
Preparing for an appointment
In most cases, complications of antiphospholipid syndrome — such as DVT, stroke or pregnancy loss — will prompt you to seek medical care. Depending on your complication, you'll likely see a specialist in vascular disease, obstetrics or hematology.
Here's some information to help you get ready for your appointment.
What you can do
Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance. Make a list of:
- Your signs or symptoms and when they began.
- Write down key personal information, including any major recent events or changes in your life.
- Key medical information, including other conditions or infections you have and family medical history, especially close relatives who've had antiphospholipid syndrome.
- All medications, vitamins and other supplements you take, including doses.
- Questions to ask your doctor.
Take a family member or friend along, if possible, to help you remember the information you get.
For antiphospholipid syndrome, some questions to ask your doctor include:
- What's the most likely cause of my symptoms?
- What tests do I need?
- What treatment do you recommend?
- How will you determine whether my treatment is working?
- Does this condition increase my risk of any other medical problems?
- Does this condition increase my risk of health problems during pregnancy? Are there treatments to reduce that risk?
- Are there brochures or other printed material that I can have? What websites do you recommend?
Don't hesitate to ask other questions, as well.
What to expect from your doctor
Questions your doctor is likely to ask include:
- Do you have a history of stroke or blood clots?
- Do you have a history of pregnancy complications, such as high blood pressure, miscarriage or stillbirth?
- Do you have lupus or another autoimmune disorder?
- Have you ever been tested for sexually transmitted infections or chronic viral diseases, such as hepatitis?
- Do you have frequent headaches?
- Have you noticed a red, net-like rash on your wrists or knees?
- Do you smoke?