Implantation is the most critical step of an IVF cycle. While many techniques have been developed to assess the embryo quality, there is still no accepted method to evaluate the endometrium at the time of implantation. The current endometrium assessment tests (e.g ERA) require biopsy which is invasive and may be detrimental to implantation if performed in the embryo-transfer cycle. Aspiration of the endometrial fluid while doing embryo transfer is non-invasive. Extracellular vesicles (EVs), including exosomes (30–150 nm) and microvesicles (100–1500 nm), play an important role in cell-to-cell communication. They have been identified in endometrial fluid of estrous/menstrual cycles in a number of animal species. In this study, we will compare the exosomes patterns of ‘implantative’ and ‘non-implantative’ endometrium obtained via endometrial fluid aspiration (EFA) at embryo transfer. Try to identify the possible markers for predicting the success of embryo implantation.