Placentation, antiphospholipid syndrome and pregnancy outcome.

The antiphospholipid antibodies (aPLs) are a diverse group of autoantibodies associated with a pattern of disease known as antiphospholipid syndrome (APS). Pregnancy complications secondary to placental insufficiency are key features of this disease. The mechanisms underlying the placental pathology remain unclear. In this article the process of placentation in healthy and pathological pregnancies is reviewed. The evidence for defective placentation in APS pregnancies and involvement of aPLs in this process is summarized. Finally hypotheses based on the interpretation of these studies are discussed.