Our results are in accordance with these later values as of 4894 ART treatment cycles we had 1.5 % of cases with suspected OHSS that was efficiently avoided with the use of a GnRH agonist for ovulation trigger, and 1 % of cases with late onset OHSS, of which 0.6 % were of moderate and 0.5 % of severe intensity. Here, GNRH1 is linked to ovarian hyperstimulation syndrome.