GNRH1 and ovarian hyperstimulation syndrome: HCG with a big carbohydrate content has a luteinizing hormone (LH) like activity with long half-life and persistent LH receptor activity (5); in contrast with HCG, GnRH agonist induces surge of both LH and FSH and has shorter activity that result in notable decrease in the risk of ovarian hyperstimulation syndrome (OHSS) (6, 7).