The presence of antiphospholipid antibodies, lupus anticoagulant and anticardiolipin antibody in patients with systemic lupus erythematosus has been associated with the clinical features of thrombosis, fetal loss and thrombocytopenia, and the syndrome is designated as antiphospholipid antibody syndrome (APS). APS has been increasingly diagnosed in patients without underlying autoimmune disease and is most frequently seen in obstetric patients suffering spontaneous abortion, preeclampsia and intrauterine growth restriction. The hypothesis underlying most research into the pathophysiology of APS is that autoantibodies are not only the markers of the disease, but also directly contribute to the development of clinical features. This review summarizes recent information on the pathophysiology and potential roles of autoantibodies in the obstetric patients suffering, particularly in the subgroup of repeated spontaneous abortions.