Chronic endometritis, chronic questions: a narrative review of current practices

Abstract

Purpose of review: Chronic endometritis is a condition that may affect reproductive outcomes, particularly in patients with unexplained infertility, recurrent implantation failure, or recurrent pregnancy loss. This review concisely summarizes the available literature, highlighting some of the controversies on this topic.

Recent findings: Although embryo selection through preimplantation genetic testing for aneuploidy has improved, many euploid embryo transfers still fail, prompting interest in endometrial factors such as chronic endometritis. Chronic endometritis is typically asymptomatic and diagnosed by identifying plasma cells in endometrial biopsy specimens; however, diagnostic criteria vary widely regarding biopsy timing, staining techniques, and threshold definitions, contributing to inconsistent prevalence and outcomes across studies. It is often attributed to chronic infection and is treated with empirical or culture-guided antibiotics, though reported cure rates vary significantly. While some studies suggest that treating chronic endometritis improves reproductive outcomes, evidence is limited by methodological heterogeneity. Meta-analyses support treatment, yet diagnostic inconsistencies and potential effects of antibiotics on the microbiome remain concerns.

Summary: While frequently diagnosed in the infertility setting, the true prevalence and impact of chronic endometritis remain unclear. The heterogeneity of the existing literature and the lack of large prospective cohort studies remain challenges to fully understanding the condition, particularly regarding the general infertile population.

Keywords: chronic endometritis; plasma cells; recurrent implantation failure; recurrent pregnancy loss.