GNRH1 and ovarian hyperstimulation syndrome: The results of this systematic review showed that in IVF-EF patients with supposed normal responses, the number of stimulation days, Gn amount, E2 value on the day of HCG, number of oocytes retrieved, and incidence of OHSS were significantly lower with the GnRH antagonist protocol than with the GnRH agonist long protocol.