Background: Bleeding is a common side effect during anticoagulant therapy. Rivaroxaban, a new anticoagulant, presents concerns regarding its association with heavy menstrual bleeding. Objectives: Our aim is to measure the prevalence of heavy menstrual bleeding in women taking rivaroxaban. We aim to measure the median Pictorial Blood Assessment Chart (PBAC) score, and its association with iron deficiency anemia (IDA), passage of clots, and age, respectively. Methods: This was a prospective, non- interventional study set in a thrombosis clinic. There were 49 patients enrolled. The study consisted of two parts: a retrospective part regarding collection of menstrual history data before starting rivaroxaban; and a prospective part using validate Arabic PBAC for the next three menstrual cycles. Main outcome measures: Prevalence of heavy menstrual bleeding among women taking rivaroxaban. Results: The median PBAC score for women taking rivaroxaban for an average of 3 months was 211, IQR (42.5, 375.9) The prevalence of heavy menstrual bleeding in women taking rivaroxaban was 22%. There is a weak correlation between IDA and age, and IDA and average PBAC score. Conclusion: Rivaroxaban may cause heavy menstrual bleeding, but it does not lead to prolongation of menstruation. A detailed menstrual history should be taken before considering rivaroxaban for women in reproductive age.