GNRH1 and ovarian hyperstimulation syndrome: Pooling the results of these RCTs showed a significant lower OHSS rate when women were treated with the GnRH antagonist protocols compared to those treated with the Long GnRH agonist protocol (RR = 0.58, 95% CI: [0.44 to 0.77]; P = 0.0002; NNTB 14, NNTB 95% CI: [11 to 26]; I2 = 0%; χ2-P = 0.59; low-quality evidence; Fig. 4).