How I diagnose and treat antiphospholipid syndrome in pregnancy

Antiphospholipid syndrome is a rare autoimmune disease characterized by arterial, venous, or microvascular thrombosis, pregnancy morbidities, or non-thrombotic manifestations in patients with persistently-positive antiphospholipid antibodies. These antibodies bind cellular phospholipids and phospholipid-protein complexes resulting in cellular activation and inflammation that ultimately lead to the clinical features of antiphospholipid syndrome, including poor placental vascularization. Our evolving understanding of the syndrome has resulted in new, more specific classification criteria. Patients meeting these criteria should be treated during pregnancy according to current guidelines, but clinicians should be aware that patients who are positive for lupus anticoagulant have at least a 30% likelihood of fetal death or early delivery for preeclampsia or placental insufficiency despite treatment. Patients with recurrent early miscarriage or fetal death in the absence of preeclampsia or placental insufficiency may not meet current classification criteria for the diagnosis of antiphospholipid syndrome. Patients with only low titer anticardiolipin or anti-beta-2 glycoprotein I antibodies or IgM isotype antibodies will not meet current classification criteria. In such cases, clinicians must understand and implement management plans that balance potential risks and benefits, some of which involve emotional concerns surrounding the patient's reproductive future. Finally, antiphospholipid syndrome may present in pregnancy or postpartum as a thrombotic microangiopathy, a life-threatening condition that may initially mimic preeclampsia with severe features but requires a very different treatment approach.