GNRH1 and ovarian hyperstimulation syndrome: As an increasingly interesting treatment, IVM becomes attracting attention. Primarily because the mature follicles can be directly ICSI for fresh embryo transfer; particularly the immature follicles can be cultured in vitro to increase the utilization rate of follicles; finally, the occurrence of ovarian hyperstimulation syndrome can be reduced, so that patients can improve the yield rate of follicles and also reduces the side effect of repeated ovarian stimulation with GnRH and gonadotropin treatment.