Heavy menstrual bleeding in women treated with rivaroxaban and vitamin K antagonists and the risk of recurrent venous thromboembolism.

Anticoagulants increase the risk of heavy menstrual bleeding (HMB). We sought to investigate the incidence, predictors and management of HMB in women on rivaroxaban compared to those on vitamin K antagonists (VKA). We addressed the issue as to whether HMB is associated with VTE recurrences. We performed a single-center prospective study in menstruating women aged 18-55years treated with rivaroxaban or VKA≥3months since the index VTE episode. Seventy six women on rivaroxaban and 45 patients on VKA were included. Patients on rivaroxaban more commonly reported HMB compared with those on VKA (31 [41%] vs. 8 [18%], p=0.009). Women treated with rivaroxaban more frequently needed interventions to reduce menstruation compared with those on VKA (29 [38%] vs. 6 [13%], p=0.004). During the median follow-up time of 13months, there were 8 (11%) recurrent VTE on rivaroxaban and 3 (7%) on VKA (p=0.5). Rivaroxaban treatment predisposed to HMB (odds ratio [OR] 3.2, 95% [confidence interval] CI 1.4-8.2, p=0.007) and the interruption of anticoagulant treatment for 2-3days (OR 3.2, 95% CI 1.1-11.6, p=0.033). HMB during the rivaroxaban treatment predisposed to recurrent VTE (OR 5.3, 95% CI 1.1-33.3, p=0.038). In menstruating women following VTE, rivaroxaban is associated with a two-fold higher risk of HMB compared with VKA. HMB predisposes to recurrent VTE episode, most likely due to the short interruptions of anticoagulation.