Recurrent venous thromboembolism and abnormal uterine bleeding with anticoagulant and hormone therapy use

Women receiving vitamin K antagonists (VKAs) require adequate contraception because of the potential for fetal complications. It is unknown if the use of hormonal therapy, especially those containing estrogens, is associated with recurrent venous thromboembolism (VTE) during anticoagulation. Despite the absence of data, World Health Organization guidelines state that use of estrogen-containing contraceptives confers an "unacceptable health risk" during established anticoagulation for VTE. We compared the incidences of recurrent VTE and abnormal uterine bleeding with and without concomitant hormonal therapy in women aged