Vaginal microbiota alterations under supraphysiological estradiol state during in vitro fertilization-embryo transfer (IVF-ET) and the association with reproductive outcomes

The process of in vitro fertilization-embryo transfer (IVF-ET) induces a maternal supraphysiological estradiol environment during embryo implantation and early development. Estrogen is crucial in modulating the colonization of microbiota within the vaginal epithelium. However, the impact of supraphysiological estradiol levels on the vaginal microbiome and the relationship with pregnancy outcomes remains unclear. The study aimed to characterize the vaginal microbiota under supraphysiological hormonal conditions.