Management of Antiphospholipid syndrome (APS) in pregnancy

Antiphospholipid Syndrome (APS) is an autoimmune disorder characterized by the presence of one or more autoantibodies against membrane phospholipids in the maternal circulation. It is an acquired condition associated with venous or arterial thrombosis and/or adverse pregnancy outcomes.

APS may occur as:

• Primary APS

• Secondary APS, usually associated with Systemic Lupus Erythematosus (SLE)

Clinical presentation

• Recurrent adverse pregnancy outcomes, including:

  • Recurrent miscarriage

  • Intrauterine growth restriction (IUGR)

  • Early severe pre-eclampsia

  • Preterm birth

• Unexplained venous thrombosis (e.g., deep vein thrombosis)

• Unexplained arterial thrombosis (e.g., stroke, myocardial infarction)

• Thrombocytopenia (common finding)

Classification criteria

Diagnosis of APS requires at least:

• One clinical criterion

AND

• One laboratory criterion

Clinical criteria

• One documented episode of arterial, venous, or small-vessel thrombosis

• One or more unexplained deaths of a morphologically normal fetus at or beyond 10 weeks of gestation

• Three or more unexplained consecutive spontaneous abortions before 10 weeks of gestation, with anatomic, hormonal, and chromosomal causes excluded

• Eclampsia or severe pre-eclampsia according to standard definitions

• Recognized features of placental insufficiency

Laboratory criteria

At least one of the following detected on two or more occasions at least 12 weeks apart:

• Anticardiolipin IgG and/or IgM antibodies

• Anti-β2 glycoprotein I IgG and/or IgM antibodies

• Lupus anticoagulant

Pharmacological treatment

1. APS without Previous thrombosis

Acetylsalicylic Acid (Aspirin)

• 75–120 mg orally once daily

• Start as soon as pregnancy is confirmed and continue throughout pregnancy

AND

Unfractionated Heparin

• 5,000–10,000 units subcutaneously

OR

Low Molecular Weight Heparin

• 30–40 mg subcutaneously once daily

2. APS with thrombosis (e.g., stroke or pulmonary embolism)

Unfractionated Heparin

• 5,000 units subcutaneous loading dose

• Followed by 15,000–20,000 units subcutaneously every 12 hours

OR

Low Molecular Weight Heparin

• 1 mg/kg subcutaneously every 12 hours

Monitoring

• Monitor activated partial thromboplastin time (aPTT) when using unfractionated heparin

• The aPTT should preferably be checked midway between the 12-hourly doses

• Target aPTT: 1.5–2.5 times the control value

Important notes

• Avoid warfarin during pregnancy because of its teratogenic effects

• Regular laboratory monitoring is required during anticoagulation therapy

Referral

• Refer immediately to a facility with expertise in managing high-risk pregnancies and capacity for laboratory monitoring of anticoagulant therapy.