Antiphospholipid syndrome (APS) is an autoimmune disorder characterized by vascular thrombosis and/or obstetric morbidity in the presence of persistent antiphospholipid antibodies (aPL) namely, lupus anticoagulant antibodies (LAC), anti-cardiolipin antibodies (aCL) and/or anti-β2-glycoprotein I antibodies. The syndrome produces a spectrum of disease, both in terms of clinical manifestations and the presence of other autoimmune conditions. The disease is classified as primary antiphospholipid syndrome (PAPS) when it occurs in the absence of any features of other autoimmune disease, and secondary where other autoimmune disease is present secondary antiphospholipid syndrome (SAPS). Upto 30% of patients with APS have minor valvular abnormalities, which usually do not cause hemodynamic disturbance. Individual treatment strategies for the management of the APS in pregnancy in part depend on the assessment of a number of different factors. The first treatment used and studied for pregnant patients with APS, was a combination of corticosteroids and low dose aspirin.

Successful pregnancy requires trophoblast invasion into the maternal uterine spiral arteries converting them into large dilated vessels. Microthrombi are frequently found in the vessels of the placentas from women who have experienced pregnancy loss and placental infarction has been described in the placentas of some, but not all, women who have a pregnancy loss and who have thrombophilia. Published meta-analyses suggest that factor V Leiden, prothrombin G20210A, and protein S deficiency are associated with an increased risk of recurrent early pregnancy loss and non-recurrent late pregnancy loss. Women with a history of pregnancy loss merit increased surveillance in subsequent pregnancies and should be given folic acid during pregnancy. Despite the lack of evidence from randomized, double-blind, placebo-controlled trials, many clinicians are offering women with a history of pregnancy loss found to have a heritable thrombophilia self-administered prophylactic doses of low molecular weight heparin daily low dose aspirin in subsequent pregnancies.