Endometrial Luteal Phase Characteristics and Luteal Phase Support in Controlled Ovarian Stimulation Protocols With GnRH Antagonists:Focusing on MicroRNA

MiRNAs are single-stranded small non-coding RNAs that act on specific mRNAs to regulate the gene expression. Studies have suggested that miRNAs influence cellular activities in the uterus, including cell differentiation and embryo implantation. In assisted reproductive cycles, controlled ovarian stimulation (COS) results in supraphysiological steroid levels and is associated with very low luteinizing hormone concentration during the luteal phase, the peri-implantation and implantation period. Luteal phase support, administration of medication aimed at supporting the implantation process, has been a routine practice in in vitro fertilization (IVF) clinics. Luteal phase support with steroid hormone has been found to improve pregnancy rates when human menopausal gonadotropins were used in conjunction with GnRH agonists for ovarian stimulation and IVF. Reports on effect of steroid supplementation in GnRH antagonist protocols are limited. The proposed project is an extension of our previous study on Endometrial Luteal Phase Characteristics and Luteal Phase Support in Controlled Ovarian Hyperstimulation Protocols with Gonadotropin Releasing Hormone Antagonists. The significance of this study is based on the importance of luteal phase endometrial after COS for the process of implantation. The availability of oocycte donors in assisted reproduction technology programs offers a unique opportunity to study the impact of different stimulation protocols on the quality of the luteal phase. In addition, the oocyte donor model may allow us to evaluate the impact of different luteal support protocols directly on the endometrial preparation by histological as well as biochemical markers. Study design: Study subjects underwent ovarian stimulation according to a gonadotropin/GnRH antagonist protocol. All donors had a baseline measurement of serum follicle stimulating hormone (FSH) and estradiol levels on the second day of their menstrual cycles. Provided serum FSH levels were less