The results of this study demonstrate that OC use appears to further increase the risk of stroke in the set- ting of endothelial dysfunction. Additional research should be focused on the validation of von Willebrand factor and ADAMTS13 as risk factors for stroke with OC use in other racial/ethnic and geographic populations, as well as explora- tion of the value of measuring these biomarkers in women before initiation of OCs. Should women be screened for thrombophilia before hor- monal contraception is prescribed for them? This question has been addressed in a large systematic review and meta- analysis of the risk of VTE in the high-risk settings of OC use Although there are 15-fold odds of VTE in women with the factor V Leiden mutation who are using OCs (95% CI, 8.66 28.15), the absolute risk is low because of the low prevalence of this and other thrombophilias and VTE. For other hereditary thrombophilias, including prothrombin gene mutation, as well as protein C and antithrombin defi- ciencies, the odds of VTE increased in combination with OC use, but the odds of VTE stayed the same with protein S defi- IS and CVT are much less common than VTE,144 so the yield of routine screening would be even lower for these conditions. Selective screening based on prior personal or family history of VTE is proposed to be more cost-effective than universal screening in women who initiate OCs or desire to become pregnant.229 The cost- effectiveness analysis in this meta-analysis was designed for prevention of VTE, but adaptation to stroke screening in young women should also include obesity, diabetes mellitus, hyperlipidemia, hyperten- sion, and cigarette smoking. 