If OHSS is not a concern, GnRH agonist can be followed by two boluses of hCG (1,500 IU each) for luteal rescue, without any additional progesterone-based luteal support.26 Thus, the triggering (high-dose) property of hCG is dissected from its luteal supportive properties (low-dose), which imitates normal physiology more closely, and yields high progesterone levels during the implantation window. This evidence concerns the gene GNRH1 and ovarian hyperstimulation syndrome.