Endometrial hyperplasia in pre-menopausal women: A systematic review of incidence, prevalence, and risk factors

•The true incidence and prevalence of endometrial hyperplasia (EH) are uncertain.•Published data are heterogeneous due to variation in populations and methodology.•Because diagnosis is invasive, estimating population prevalence is challenging.•Here, we describe the incidence and prevalence of EH in large, published studies.•We provide an overview of factors that might influence observed rate differences.