Abstract
This systematic review and meta-analysis of randomized controlled trials aimed to evaluate the effect of a single-dose gonadotropin-releasing hormone agonist administration in the frozen-thawed embryo transfer cycle on pregnancy outcomes. A literature search was strategically conducted using PubMed, EMBASE, and the Cochrane Controlled Trials Register. The primary outcome was the clinical pregnancy rate. The secondary outcomes combined chemical pregnancy rate, implantation rate, ongoing pregnancy rate, live birth rate, miscarriage rate, and extrauterine pregnancy rate. Out of the 1594 citations that were found, only six met the criteria for being included in the meta-analysis. The clinical pregnancy rate was higher in the treatment group than in the control group (52.05% vs. 47.29%; p=0.04; RR=1.09; 95% CI=1.00-1.18). According to subgroup analysis based on the natural cycle, the clinical pregnancy rate with the agonist administration is significantly higher (43.75% vs. 27.35%; p=0.01; RR=1.6; 95% CI=1.10-2.32). However, there was no difference between the groups in terms of artificial cycles (p=0.80; 95% CI=0.96-1.20). The secondary outcomes did not show significant differences. We concluded that supplementing with a single dose of gonadotrophin-releasing hormone agonist can marginally increase the clinical pregnancy rate, particularly in the natural cycle. Other pregnancy outcomes do not improve with the treatment.