Combined Hormonal Contraceptives and First Venous Thrombosis in Young French Women: Impact of Thrombotic Family History

CONTEXT: In UK and French, but not World Health Organization (WHO), guidelines for combined hormonal contraception (CHC), family history of a venous thromboembolism (VTE) is a condition for which the theoretical risks usually outweigh the advantages of using CHC. OBJECTIVE: We estimated the prevalence of inappropriate prescriptions of CHC according to several international guidelines and their impact on VTE. DESIGN: A single-center observational study. SETTING: Hemostasis unit outpatient clinic (Paris, France). POPULATION: A total of 2088 French CHC users of childbearing age with a first documented VTE who were referred to our unit between 2000 and 2009. METHODS: Data were collected by a standardized questionnaire during a medical consultation. Family history of VTE was analyzed according to definitions from international recommendations (VTE before age 45 years, United Kingdom; before age 50 years, France). A CHC prescription was considered inappropriate for women with vascular contraindications and/or a family history of VTE. Cross-sectional analysis of the clinical and biological characteristics was performed. MAIN OUTCOME MEASURES: Prevalence of inappropriate prescription of CHC and potentially preventable events were estimated. RESULTS: According to the WHO, UK, or French guidelines, 8.8%, 18.9%, and 25.9%, respectively, of CHC prescriptions were considered inappropriate. Compliance with these guidelines could reduce the corresponding number of VTEs by 6.3%, 13.5%, and 18.5%, respectively. Characteristics of the women were similar. CONCLUSION: Our results suggest inappropriate CHC prescriptions are prevalent among CHC users with first VTE. The appropriate way to take family history of VTE into account should be further clarified.