GNRH1 and ovarian hyperstimulation syndrome: When compared with GnRH agonists, the advantages of the GnRH antagonists include: Shortening the treatment duration in ovulation induction applications, decreasing the used exogenous gonadotropin amount, decreasing the frequency of hypo-estrogenic symptoms, decreasing the risk of functional cyst development risk, decreasing the incidence of ovarian hyper-stimulation syndrome (OHSS)(7).