A Systematic Review and Meta-Analysis of Single-Dose GnRH Agonist on the Day of Frozen Embryo Transfer in Artificial Cycles: Preliminary Evidence from Randomized Trials

<b>Background/Objectives</b>: GnRH agonists may offer potential benefits when used for luteal phase support in assisted reproductive treatments. This systematic review and meta-analysis of randomized controlled trials evaluates the effect of a single-dose administration of gonadotropin-releasing hormone (GnRH) agonist on the day of frozen-thawed embryo transfer (FET) in artificial cycles, in terms of reproductive outcomes. <b>Methods</b>: A comprehensive literature search was performed using the PubMed and Cochrane databases to identify relevant studies. The outcomes assessed were live birth rate, clinical pregnancy rate, positive pregnancy test, implantation rate, and miscarriage rate. Three randomized controlled trials were included in the analysis. <b>Results</b>: The clinical pregnancy rate (56.5% vs. 47.4%; OR 1.27; 95% CI: 1.01-1.60; <i>p</i> = 0.0426) and live birth rate (34.3% vs. 23.9%; OR 1.71; 95% CI: 1.00-2.91; <i>p</i> = 0.0483) were significantly higher in the treatment group compared to the control group. No statistically significant differences were observed between the groups in terms of positive pregnancy test, implantation rate, or miscarriage rate, although the analysis revealed a trend toward improved outcomes in the intervention group. <b>Conclusions</b>: In summary, although our meta-analysis indicates that a single dose of GnRH agonist in artificial FET cycles may be associated with improved clinical pregnancy and live birth rates, these findings are based on a limited number of available trials. Larger, well-designed randomized controlled trials are urgently needed before any changes to clinical recommendations can be justified.