Gonadotropin-releasing hormone antagonist (GnRH-ant) cycles are characterized by higher patient acceptability with more attention being directed to the potential effect of steroid pretreatment to program antagonist protocol cycles, as marked size discrepancies of growing follicles reflect incoordinated maturation of follicular-oocyte complexes and complicates clinical criteria for human chorionic gonadotropin (hCG) administration. This phenomenon is associated with fewer mature oocytes and resulting embryos, which limits sufficient embryo selection for embryo transfer. Indeed, the large number of available embryos represented an important prognostic factor of invitro-fertilization (IVF) outcome, particularly in poor prognosis patients, possibly by increasing the probability that at least one good-quality embryo will be selected for embryo transfer. During COH, a better understanding of follicular development has resulted in the improvement of strategies for ovarian stimulation. This approach represents a potential and more physiological alternative to GnRH agonist or oral contraceptive pills pre-treatment in a trial to synchronize multi-follicular development and improve controlled ovarian hyperstimulation (COH) results. The present study is a randomized controlled trial that investigated whether E2 pre-treatment during the luteal phase affects developmental characteristics of growing follicles during COH. It depended on the hypothesis that growth asynchrony of antral follicles is a consequence of the gradual FSH elevation that occurs during the late luteal phase, thus testing for detection of the effect of luteal estradiol on follicular synchronization and its effect on ICSI outcome.
Depended on the hypothesis that growth asynchrony of antral follicles is a consequence of the gradual follicle stimulating hormone (FSH) elevation that occurs during the late luteal phase, the aim of this work is to study the effect of estradiol pretreatment on follicular synchronization and intracytoplasmic sperm injection (ICSI) outcome in antagonist cycles