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.