A systematic review on the prevalence of endometriosis in women

Background & objectives: Endometriosis is one of the causes of female infertility, but the prevalence of endometriosis is not exactly known. We conducted a systematic review and meta-analysis to provide an estimate of the prevalence of endometriosis in women considering the stage of disease, diagnostic method, geographical distribution, clinical symptoms and sample size. Methods: MEDLINE, Web of Science, Google Scholar, Scopus and Cumulative Index of Nursing and Allied Health were searched to identify peer-reviewed studies published from January 1990 to December 2018 reporting the prevalence of endometriosis. Relevant additional articles were identified from the lists of the retrieved articles. Studies with cross-sectional design were included in the meta-analysis. Results: The overall prevalence of endometriosis was 18 per cent [95% confidence interval (CI): 16-201 and the prevalence of endometriosis by stage ranged from two per cent (95% CI: 1-4) for stage 4 to 20 per cent (95% CI: 11-28) for stage 1. The prevalence levels of endometriosis in women with infertility, chronic pelvic pain and asymptomatic were 31 (95% CI: 15-48), 42 (95% CI: 25-58) and 23 per cent (95% CI: 19-26), respectively. Interpretation & conclusions: The results of this study showed that the prevalence of endometriosis in developing countries was high. Future studies are needed to explore other factors affecting the prevalence of endometriosis worldwide, which may help develop future prevention programmes.