Cumulative live birth rates between GnRH-agonist long and GnRH-antagonist protocol in one ART cycle when all embryos transferred: real-word data of 18,853 women from China

Background A consensus has been reached on the preferred primary outcome of all infertility treatment trials, which is the cumulative live birth rate (CLBR). Some recent randomized controlled trials (RCTs) and retrospective studies have compared the effectiveness of GnRH-antagonist and GnRH-agonist protocols but showed inconsistent results. Studies commonly used conservative estimates and optimal estimates to described the CLBR of one incomplete assisted reproductive technology (ART) cycle and there are not many previous studies with data of the complete cycle to compare CLBRs in GnRH-antagonist versus GnRH-agonist protocols. Methods A total of 18,853 patients have completed their first IVF cycle including fresh and subsequent frozen-thawed cycles during 2016-2019, 16,827 patients were treated with GnRH-a long and 2026 patients with GnRH-ant protocol. Multivariable logistic analysis was used to evaluate the difference of GnRH-a and GnRH-ant protocol in relation to CLBR. Utilized Propensity Score Matching(PSM) for sampling by up to 1:1 nearest neighbor matching to adjust the numerical difference and balance the confounders between groups. Results Before PSM, significant differences were observed in baseline characteristics and the CLBR was 50.91% in the GnRH-a and 33.42% in the GnRH-ant (OR = 2.07; 95%CI: 1.88-2.28; P < 0.001). Stratified analysis showed the CLBR of GnRH-ant was lower than GnRH-a in suboptimal responders(46.89 vs 27.42%, OR = 2.34, 95%CI = 1.99-2.74; P < 0.001) and no differences of CLBR were observed in other patients between protocols. After adjusting for potential confounders, multivariable logistic analysis found the CLBR of GnRH-ant group was lower than that of GnRH-a group (OR = 2.11, 95%CI:1.69-2.63, P < 0.001). After PSM balenced the confounders between groups, the CLBR of GnRH-a group was higher than that of GnRH-ant group in suboptimal responders((38.61 vs 28.22%, OR = 1.60, 95%CI = 1.28-1.99; P < 0.001) and the normal fertilization rate and number of available embryo in GnRH-a were higher than these of GnRH-ant groups in suboptimal responders (77.39 vs 75.22%; 2.86 +/- 1.26 vs 2.61 +/- 1.22; P < 0.05). No significant difference was observed in other patients between different protocols. Conclusions It is crucial to optimize the utilization of protocols in different ovarian response patients and reconsider the field of application of GnRH-ant protocols in China.

Automated summary

In patients with suboptimal ovarian response, the CLBR of the GnRH-antagonist protocol was lower than that of the GnRH-agonist protocol, but there was no significant difference in CLBR between the two protocols in other patients. After balancing and adjusting for confounders between the groups, the results suggested that the GnRH-agonist protocol had a higher CLBR in patients with suboptimal ovarian response.