Incidence of pregnancy outcomes among patients with recurrent implantation failure: a systematic review and meta-analysis

Abstract

Background: Globally, there is no conclusive data on the pregnancy outcomes of patients with recurrent implantation failure (RIF) who received the next embryo transfer. The purpose of this study is to summarize the pregnancy outcomes of patients with RIF after embryo transfer and understand the disease burden of patients with RIF. Methods: We searched for literature from databases such as PubMed, Web of Science, Embase, and Cochrane Central Register of Controlled Trials from inception to May 19, 2024, and extracted the pregnancy outcomes of patients with RIF in the blank control group, including implantation rate (IR), clinical pregnancy rate (CPR), ongoing pregnancy rate (OPR), miscarriage rate (MR), live birth rate (LBR), and ectopic pregnancy rate (EPR). Subsequently, meta-analyses of the rates were summarized and subgroup analyses were performed based on implantation failures, embryo type, fresh/frozen embryo transfer and regions. Results: A total of 110 studies (14,159 patients) were included in the meta-analysis. Globally, the overall IR, CPR, OPR, MR, LBR, and EPR of patients with RIF were 19.3%, 29.4%, 24.6%, 19.9%, 23.0%, and 0.9%, respectively. No differences in pregnancy outcomes were found between RIF patients with three or more implantation failures and those with two or more implantation failures. RIF patients who transferred blastocyst achieved significantly higher IR, higher CPR, higher OPR, higher LBR and lower EPR, but no lower MR. There are differences in IR and CPR among patients with RIF in different regions, and no significant differences in other pregnancy outcomes. Conclusion: This study summarizes the global pregnancy outcomes of patients with RIF who undergo subsequent embryo transfer. Pregnancy outcomes in patients with RIF may not be related to the number of implantation failures. Frozen blastocyst transfer is recommended for patients with RIF. Pregnancy outcomes in patients with RIF vary across regions. Protocol registration: This study has been registered on PROSPERO (CRD 42024539968).