Risk factors

Risk factors for antiphospholipid syndrome include:

• Your sex. This condition is much more common in women than in men.
• Immune system disorders. Having another autoimmune condition, such as lupus or Sjogren's syndrome, increases your risk of antiphospholipid syndrome.
• Infections. This condition is more common in people who have certain infections, such as syphilis, HIV/AIDS, hepatitis C or Lyme disease.
• Medications. Certain medications have been linked to antiphospholipid syndrome. They include hydralazine for high blood pressure, the heart rhythm-regulating medication quinidine, the anti-seizure medication phenytoin (Dilantin) and the antibiotic amoxicillin.
• Family history. This condition sometimes runs in families.

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