The Role of the Physiological Endometrial Microbiota in Assisted Reproduction Outcomes

The goal of this observational study is to investigate the influence and contribution of the normal composition and balance of the endometrial microbiota on the achievement of embryo implantation and the maintenance of pregnancy in women undergoing IVF, with comparable clinical profiles, including patients with a history of RIF or RPL, evaluated under identical treatment protocols and hormonal conditions. The main questions it aims to answer are: 1. Does the normal composition of the endometrial microbiota, particularly the dominance of Lactobacillus species, influence embryo implantation success in women undergoing IVF? 2. Does the endometrial microbiota profile affect pregnancy maintenance, ongoing pregnancies, and live birth rates in women with a history of recurrent implantation failure (RIF) or recurrent pregnancy loss (RPL) Participants will not undergo any additional interventions beyond standard clinical care.They will provide clinical data already collected as part of routine IVF procedures.