F2 and thrombophilia: It has been shown that inherited thrombophilia such as factor V Leiden (FVL) mutation, prothrombin mutation, methylene tetra hydrofolate reductase (MTHFR) mutation, and deficiencies in proteins S and C and antithrombin III, and acquired thrombophilia like lupus anticoagulant and anticardiolipin may have critical role in implantation failure (4, 5).