Due to the effectiveness of the GnRH-a trigger, limited data has subsequently been published on other potential interventions for OHSS prevention/reduction in GnRH-ant co-treated cycles, with conventional hCG triggering or in GnRH-a controlled cycles which are still widely performed globally and in trials exploring new gonadotropin formulations [19–21]. This evidence concerns the gene GNRH1 and ovarian hyperstimulation syndrome.