Defects in Coagulation Factors Leading to Recurrent Pregnancy Loss

Haemostasis is a complex and highly regulated process that implicates many pro- and anticoagulation proteins. Qualitative or quantitative defects in one of these proteins may cause a tendency to throm-bosis defined as thrombophilia, which can be hereditary or acquired. The evidence for pregnancy loss having a thrombotic basis is due to the association between antiphospholipid antibodies (aPLs), which is an acquired thrombophilia, and recurrent pregnancy loss (RPL). Due to the assumption that aPL induces thrombosis causing pregnancy loss, it has been assumed that any prothrombotic state may also increase the chance of pregnancy loss due to a thrombotic mechanism. Hereditary thrombophilias have been classified as: (1) defects/decrease in coagulation inhibitors (antithrombin, protein C, protein S, tissue factor pathway inhibitor and thrombomodulin); (2) increased levels or function of procoagulation factors such as prothrombin (factor V Leiden [FVL], prothrombin gene mutation G20210A); and (3) decreased/impaired lysis of blood clot (factor XIII deficiency, dysfibrinogenemia and afibrinogenemia/hypofibrinogenemia).