Objective: To assess the effects of the levonorgestrel-releasing intrauterine system (LNG-IUS) on standard cardiovascular risk markers among women with thrombophilia and/or previous venous thromboembolism (VTE).Methods: A prospective cohort study enrolled women aged 18-45 years with thrombophilia and/or a history of VTE who received the 52-mg LNG-IUS (20 μg/d initial release) at the University of Ribeirão Preto Medical School, Brazil, from January 2006 to December 2015. Before and 12 months after LNG-IUS placement, the following cardiovascular risk markers were assessed: lipid profile, body mass index (BMI), blood glucose, systolic blood pressure, diastolic blood pressure, and waist circumference. The primary outcome was changes in cardiovascular risk markers. A subanalysis of anticoagulant users versus non-users was also conducted.Results: In total, 45 women were enrolled. BMI increased by 2.3% after 12 months of LNG-IUS placement (P < 0.01), but the other risk factors did not change. Cardiovascular risk markers were similar between anticoagulant users and non-users after 12 months of LNG-IUS use.Conclusion: Among women with thrombophilia and/or previous VTE, cardiovascular risk markers were not found to change significantly after 12 months of LNG-IUS use. The study adds safety information regarding use of the LNG-IUS for women at risk of thromboembolism. [ABSTRACT FROM AUTHOR]