The overall adult incidence of and is higher in women (1.86 per 100000; 95% CI, 1.44 2.36) This sex difference is even more notable in women aged 31 to 50 years, in whom the incidence may be as high as 2.78 per 100000 person-years (95% CI, 1.98 3.82). Women tend to be younger (median age 34 years) than men (median age 42 years) at the time of diagnosis.193,198 Guidelines for the evaluation and treatment of CVT were published recently.200 Therefore, only interim studies with an emphasis on sex- specific factors are presented in this guideline. Risk Factors The female predominance of CVT has been attributed to hormonal factors (primarily oral contraceptive [OC] use and pregnancy), because the incidence is sex-independent in chil- dren and in the elderly.201,202 A link between thrombophilia and CVT has been relatively well established for several inherited conditions, including antithrombin III, protein C, and protein S deficiency and factor V Leiden.200 Many exogenous provok- ing factors for venous thrombosis have been described, such as cancer, infection, and hematologic and autoimmune condi- However, 2 major risk factors are female specific: OC use and pregnancy. The use of OCs is associated with an increased risk of CVT,200 a risk that is increased significantly in women with an underlying hereditary prothrombotic fac- tor, such as factor V Leiden or prothrombin gene mutation.203 Pregnancy and OC use are considered transient risk factors and do not necessarily indicate a higher risk for recurrence. 