What is antiphospholipid syndrome, and how does it cause recurrent miscarriage?

Antiphospholipid syndrome (APS) is an autoimmune disorder with persistent antiphospholipid antibodies (lupus anticoagulant, anticardiolipin, or anti-beta2-glycoprotein-I) plus clinical features (thrombosis or pregnancy morbidity).

It causes recurrent miscarriage through placental thrombosis and impaired trophoblast function/placentation - leading to miscarriage, fetal death, severe pre-eclampsia, and growth restriction.

Clinical relevance. Identifying APS (the key treatable cause) enables aspirin+heparin treatment that markedly improves live-birth rates.

More Detail

Antiphospholipid syndrome

APS is the most important treatable cause of recurrent miscarriage.

Diagnosis

• Requires a clinical criterion (vascular thrombosis, or pregnancy morbidity - e.g. >=3 consecutive early losses, fetal death >=10 weeks, or severe early pre-eclampsia/placental insufficiency) plus a laboratory criterion.
• Antibodies (persistently positive, >=12 weeks apart) - lupus anticoagulant, anticardiolipin, or anti-beta2-glycoprotein-I.

How it causes miscarriage

• Placental thrombosis (a prothrombotic state) and impaired trophoblast invasion and placentation.
• Leads to recurrent miscarriage, late fetal death, severe pre-eclampsia, and fetal growth restriction.

Why it matters

• It is treatable - low-dose aspirin plus heparin substantially improves live-birth rates (see treatment card).