Administration of GnRH antagonist in the luteal phase appears to result in rapid resolution of severe OHSS as early as two days after initiation of GnRH antagonist, with a significant decline of ovarian volume, hematocrit and ascites, as well as oestradiol and progesterone concentrations, confirming previous reports published in three small case series[22-24]. This evidence concerns the gene GNRH1 and ovarian hyperstimulation syndrome.