GNRH1 and ovarian hyperstimulation syndrome: With the development of the gonadotropin-releasing hormone (GnRH) antagonist protocol in theory and application, GnRH antagonists have become widely used tools for controlled ovarian stimulation (COS) cycles because of its advantages, including its shorter duration of stimulation, low cost, and low incidence of ovarian hyperstimulation syndrome (OHSS) [1–3].