Vaginal and endometrial microbiome: evaluation, effect on embryo implantation

Objective : assessment of the microbiome of the vagina and uterine cavity using a uterine catheter with a collet guide in infertile patients before the in vitro fertilization procedure. Materials and methods : samples of vaginal and endometrial scrapings obtained from 73 infertile women who had planned an in vitro fertilization (IVF) procedure were taken and studied. The samples were analyzed by V3-V4-V6 regions using the 16S rRNA gene sequencing method. Results : significant differences were found in the taxonomy of the endometrium and vaginal microbiome - coincidences in microbiological composition were detected in 18.2% of patients. Endometrial lactobacillus-dominant microbiocenoses occurred in 24.8% of women, vaginal — in 56.7%. Comparisons between patients with negative and positive IVF (onset of biological pregnancy) results failed to identify any microorganism associated with the success of the procedure, with endometrial microbiota biodiversity being higher among women who successfully exercised their reproductive function. The Shannon Equality Index (J) for pregnant and non-pregnant women was 0.76 (0.57–0.87) and 0.55 (0.51–0.64), respectively (p=0.002). Conclusion : the use of a developed uterine catheter with a collet guide for an adequate assessment of the endometrial microbiome is promising and justified. The correct assessment of the endometrial microbiocenosis contributes to the adequate diagnosis of pathological processes occurring in the uterine cavity, which will allow for proper therapy aimed at increasing the receptivity of the endometrium and, in the future, contributing to the realization of the reproductive function of a woman.