F5 and Rare hereditary thrombophilia: Because of the high prevalence of FII G20210A and FV Leiden mutations in the Spanish population (6.5% and 2%, respectively) and the increased risk of VTE in COC users (3 times higher for the prothrombin mutation and 1.4 times higher for the FV mutation), the authors of another study recommend genetic screening in women from families with thrombophilia before prescribing COCs [88].