Gonadotrophin-releasing hormone antagonist regimen versus agonist regimen among normal ovarian responders: a systematic review and meta-analysis

This systematic review and meta-analysis compared the efficacy and safety of gonadotrophin-releasing hormone antagonist (GnRH-ant) versus GnRH agonist (GnRH-a) regimens in women with a normal ovarian response undergoing controlled ovarian stimulation. PubMed, Embase, Cochrane Library, CNKI, VIP, and Wanfang were searched from inception to April 30, 2024. Randomized controlled trials were independently screened, appraised for risk of bias, and synthesized using meta-analysis. Eight RCTs involving 1,841 participants were included. Compared with GnRH-a, GnRH-ant was associated with fewer retrieved oocytes (WMD -0.77, 95% CI -1.35 to -0.20; P=0.009) and a lower implantation rate (RR 0.75, 95% CI 0.60 to 0.93; P=0.009), but required less total gonadotrophin (WMD -389.65; P<0.001) and a shorter stimulation duration (WMD -2.00 days; P<0.001). GnRH-ant reduced the risk of ovarian hyperstimulation syndrome (OHSS) (RR 0.33, 95% CI 0.11 to 0.94; P=0.037). Clinical pregnancy (RR 0.84, P=0.056) and abortion rates (RR 1.13, P=0.729) were comparable. Taken together, GnRH-ant reduced gonadotrophin exposure, shortened stimulation, and lowered OHSS risk, but produced slightly fewer oocytes and a lower implantation rate; clinical pregnancy and abortion rates did not differ significantly between regimens.