GNRH1 and ovarian hyperstimulation syndrome: A systematic review of 5 randomised controlled trials (RCTs), conducted by Al-Inany in 2001 [1], showed that compared with the GnRH agonist long protocol, the GnRH antagonist fixed protocol showed a significantly reduced stimulation time and Gn amount, along with lower oocyte retrieved numbers and clinical pregnancy rates, whereas the incidence of severe ovarian hyperstimulation syndrome (OHSS) was not significantly different between the 2 treatment regimens.