Purpose of review: Presence of antiphospholipid antibodies (aPL) is associated with unsuccessful pregnancy outcome. Based on an early concept of aPL-induced thrombophilia and placental thrombosis, antithrombotic interventions have been used to reduce incidence of miscarriage in antiphospholipid antibody syndrome (APS). The aim of this review is to summarize current knowledge on pathogenesis of miscarriage in APS and the impact of different antithrombotic therapy strategies.
Recent findings: Pathogenetic concepts on miscarriage in APS comprise aPL-mediated cell activation, disturbance of coagulation along with increased complement activation. There is increasing evidence that heparin exerts its effect by inhibiting complement activation rather than by its anticoagulation capacity. In this regard, the outcome of pregnancies in APS has considerably improved by the invention of therapies using combinations of aspirin, unfractionated heparin (UFH) and/or low molecular weight heparin (LMWH). However, there is no clear evidence as to which treatment regimen should be preferred. Some studies indicate superiority of aspirin plus heparin over aspirin-only. Whether heparin-only treatment would confer equal effects and whether UFH and LMWH were of comparable efficacy currently is unknown.
Summary: Treatment with aspirin and heparin decreases the risk of miscarriages in APS. Well designed trials as well as better patients-at-risk profiling are warranted that identify which treatment strategy should be favored and whether detailed characterization of aPL specificities could help in individualizing therapy.