RESUMEN
Background: Heavy menstrual bleeding (HMB) detrimentally effects women. It is important to be able to compare treatments and synthesise data to understand which interventions are most beneficial, however, when there is variation in outcome reporting, this is difficult. Objectives: To identify variation in reported outcomes in clinical studies of interventions for HMB. Materials and Methods: Searches were performed in medical databases and trial registries, using the terms 'heavy menstrual bleeding', menorrhagia*, hypermenorrhoea*, HMB, "heavy period "period", effective*, therapy*, treatment, intervention, manage* and associated MeSH terms. Two authors independently reviewed and selected citations according to pre-defined selection criteria, including both randomised and observational studies. The following data were extracted- study characteristics, methodology and quality, and all reported outcomes. Analysis considered the frequency of reporting. Results: There were 14 individual primary outcomes, however reporting was varied, resulting in 45 specific primary outcomes. There were 165 specific secondary outcomes. The most reported outcomes were menstrual blood loss and adverse events. Conclusions: A core outcome set (COS) would reduce the evident variation in reporting of outcomes in studies of HMB, allowing more complete combination and comparison of study results and preventing reporting bias. What is new?: This in-depth review of past research into heavy menstrual bleeding shows that there is the need for a core outcome set for heavy menstrual bleeding.