Purpose: Recurrent implantation failure (RIF) is a common cause of disappointment and a big challenge after assisted reproduction technology treatments. The objective of this study was to evaluate the existing literature to explore whether peripheral blood mononuclear cells' (PBMCs) instillation could improve pregnancy outcomes among patients with RIF.
Methods: We conducted a comprehensive search including PubMed, EMBASE, Cochrane library and various databases in China. Three randomized controlled trials (RCTs) and three non-randomized controlled trials (non-RCTs) were included. We included subgroup and sensitivity analyses using Stata 12.0.
Results: The results of the three RCTs showed that PBMC improved outcomes in all patients compared with placebo or no-treatment [clinical pregnancy rate (CPR): odds ratio (OR) 2.45, 95% confidence interval (CI) 1.53-3.91; implantation rate (IR): OR 2.46, 95% CI 1.48-4.09; live birth rate (LBR): OR 2.43, 95% CI 1.32-4.49]. However, the results of the three non-RCTs indicated that there were no statistically significant differences in the outcomes and that the heterogeneity was higher (I2 > 0%). Subgroup analysis further suggested that PBMCs treatment significantly increased the CPR, IR and LBR in the three or more implantation failure subgroups (CPR: OR 2.83, 95% CI 1.29-6.22; IR: OR 3.74, 95% CI 1.71-8.19; LBR: OR 3.03, 95% CI 1.15-7.98).
Conclusions: Among patients with three or more implantation failures, this treatment improved IR, LBR, and CPR compared to that in controls, due to the limited data available, PBMCs' intrauterine instillation should only be used in the context of clinical trials.
Keywords: Assisted reproductive technology; In vitro fertilization; Peripheral blood mononuclear cell; Recurrent implantation failure.