Antiphospholipid Syndrome Screening and Management

Indications for Screening

The American Heart Association recommends screening for antiphospholipid syndrome (APLS) in patients with recurrent pregnancy loss (≥3 miscarriages before 10 weeks gestation), unexplained thrombotic events (especially in young adults <50 years), cryptogenic stroke/TIA, or a history of venous thromboembolism, as these populations have the highest yield for diagnosis and benefit most from targeted anticoagulation therapy 1, 2, 3
Screen women with ≥3 early pregnancy losses (before 10 weeks gestation), as this threshold triggers strong treatment recommendations and represents the most common obstetric manifestation of APLS 2, 3
Screen patients with cryptogenic stroke or TIA, particularly those under 50 years of age, as the association between antiphospholipid antibodies and stroke is strongest in younger adults 1, 4, 5

Diagnosis requires BOTH persistent laboratory positivity AND clinical criteria to be met, with testing for lupus anticoagulant (LAC), anticardiolipin antibodies, and anti-β2-glycoprotein I antibodies using standardized ELISA 2
Repeat testing after 12 weeks to confirm persistence, as transient positivity does not meet diagnostic criteria and does not warrant treatment 2

For obstetric APLS: Initiate prophylactic or intermediate-dose LMWH plus low-dose aspirin (75-100 mg daily) throughout pregnancy and for at least 6 weeks postpartum, as recommended by the American College of Obstetricians and Gynecologists 2, 3
For thrombotic APLS: Use therapeutic-dose LMWH (or 75% of therapeutic dose) plus low-dose aspirin throughout pregnancy and postpartum, as recommended by the American Heart Association 2, 3
For stroke/TIA with full APLS syndrome: Anticoagulation with warfarin targeting INR 2-3 is reasonable over higher intensity anticoagulation (INR >3) to balance bleeding risk against thrombosis risk, as recommended by the American Stroke Association 1

Never use rivaroxaban in patients with triple-positive antibodies (lupus anticoagulant, anticardiolipin, and anti-β2GPI), as it is associated with excess thrombotic events compared to warfarin, according to the American Heart Association 1
Do not use direct oral anticoagulants (DOACs) in pregnancy, as they are contraindicated due to safety concerns, as recommended by the American College of Obstetricians and Gynecologists 2
Avoid vitamin K antagonists in the first trimester (teratogenic) and from week 36 onwards (fetal intracranial bleeding risk), as recommended by the American College of Obstetricians and Gynecologists 2