Concerning the FSH dose decrease strategy, a systematic review without data synthesis [37], including 18 studies published from 2007 to 2017 for 6630 IVF cycles in which patients received a gonadotropin ovarian stimulation that allowed dose adjustment within the study protocol and that reported at least one dose adjustments of conventional r-FSH, concluded that decreasing the r-FSH dose during the mid-follicular phase of the ovarian stimulation may reduce the occurrence of OHSS compared to a fixed FSH dosage [37]. This evidence concerns the gene BRD2 and ovarian hyperstimulation syndrome.