Efficacy of oxytocin antagonist infusion in improving in vitro fertilization outcomes on the day of embryo transfer: A meta-analysis

OBJECTIVE: Uterine contraction induced by the embryo transfer (ET) process has an adverse effect on embryo implantation. The aim of this study was to determine the effect of oxytocin antagonist supplementation on the day of ET on in vitro fertilization outcomes via a meta-analysis. METHODS: We performed a meta-analysis of randomized controlled trials (RCTs). Four online databases (Embase, Medline, PubMed, and Cochrane Library) were searched through May 2015 for RCTs that investigated oxytocin antagonist supplementation on the day of ET. Studies were selected according to predefined inclusion criteria and meta-analyzed using RevMan 5.3. Only RCTs were included in this study. The main outcome measures were the clinical pregnancy rate, the implantation rate, and the miscarriage rate. RESULTS: A total of 123 studies were reviewed and assessed for eligibility. Three RCTs, which included 1,020 patients, met the selection criteria. The implantation rate was significantly better in patients who underwent oxytocin antagonist infusion (19.8%) than in the control group (11.3%) (n=681; odds ratio [OR], 1.92; 95% confidence interval [CI], 1.25–2.96). No significant difference was found between the two groups in the clinical pregnancy rate (n=1,020; OR, 1.57; 95% CI, 0.92–2.67) or the miscarriage rate (n=456; OR, 0.76; 95% CI, 0.44–1.33). CONCLUSION: The results of this meta-analysis of the currently available literature suggest that the administration of an oxytocin antagonist on the day of ET improves the implantation rate but not the clinical pregnancy rate or miscarriage rate. Additional, large-scale, prospective, randomized studies are necessary to confirm these findings.