KISS1 and ovarian hyperstimulation syndrome: Thus, to safeguard participant well being throughout this study of patients at high risk of developing OHSS, a clinical decision was requested from the senior IVF study clinician (G.T.)prior to kisspeptin-54 trigger administration in all patients with more than 18 follicles of at least 11 mm or a serum estradiol greater than 18 000 pmol/L on the day of kisspeptin-54 trigger administration as to whether to proceed with fresh embryo transfer or to recommend segmentation (cryopreservation of all embryos with embryo transfer in a subsequent cycle).