1. Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by arterial or venous thrombosis or pregnancy morbidity in the presence of antiphospholipid antibodies. 2. The diagnosis of APS requires one clinical criterion of vascular thrombosis or pregnancy morbidity and one laboratory criterion of positive testing for antiphospholipid antibodies on two occasions at least 12 weeks apart. 3. Treatment for APS in pregnancy involves low-dose aspirin and heparin starting at a positive pregnancy test through 34 weeks of gestation to reduce the risk of pregnancy complications like miscarriage, preeclampsia, and intrauterine growth restriction.