Correlations between Gut Microbial Composition, Pathophysiological and Surgical Aspects in Endometriosis: A Review of the Literature

Background and Objectives: Endometriosis is an estrogen-dependent, inflammatory, gynecological disorder represented by the migration of endometrial tissue outside the uterus. It can manifest through gynecological and gastrointestinal (GI) signs. Given the hormonal imbalances in endometriosis and the effect of microbiota on immune dysfunction, it has been thought that the human microbiome may play a role in its pathogenesis, acting differently before and after laparotomy. The aim of this review is to establish whether there is an interaction between endometriosis and gut microbial composition. Materials and Methods: We aimed to review available literature by systematically searching five databases: PubMed, EMBASE, Scopus, Cochrane Library, and ScienceDirect. We included records describing gut microbiota in the context of endometriosis—observing PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines—to recognize the presence of disease by the expression of bacterial taxa—based on 16S ribosomal RNA gene sequencing analysis. Results: Among 10 studies selected, there were four review articles and six clinical trials. The latter identified significant differences at a genus level in increased Prevotella, Blautia, and Bifidobacterium and decreased Paraprevotella, Ruminococcus, and Lachnospira (p < 0.05). In patients undergoing abdominal hysterectomy, Proteobacteria phylum increased from 34.36% before surgery to 54.04% after surgery (p < 0.05). Conclusions: Although scientific literature reports different characterizations of intestinal microbiota in endometriotic patients, further evidence is needed to develop new diagnostic-therapeutic strategies, for example, administration with probiotics before surgery.