Comparing the effect of sequential embryo transfer versus double blastocyst embryo transfer on pregnancy outcomes in intracytoplasmic sperm injection (ICSI) cycles in patients with repeated implantation failure: A randomized controlled trial

The effect of sequential embryo transfer on pregnancy outcomes in patients with recurrent implantation failure: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The aim of our study was to assess the impact of sequential embryo transfer on pregnancy outcomes among patients with recurrent implantation failure (RIF).

METHODS

We conducted a comprehensive search across various databases for eligible clinical trials from inception to January 2024. Randomized controlled trials (RCTs) were included if they compared sequential embryo transfer, comprising both cleavage-stage and blastocyst-stage embryos, with other transfer protocols in infertile women with repeated implantation failure. Meta-analysis was performed using Revman software. Our primary focus was on the ongoing pregnancy rate. Our secondary measures included rates of chemical pregnancies, clinical pregnancies, miscarriages, and multiple pregnancies.

RESULTS

Seven RCTs, encompassing 909 patients, met the inclusion criteria. Sequential embryo transfer demonstrated a significant increase in the ongoing pregnancy rate compared to the control group (OR = 2.28, 95% CI [1.46, 3.56], p = 0.003). Moreover, the sequential embryo transfer group exhibited notable improvements in chemical and clinical pregnancy rates. There were no statistically significant differences between the groups regarding multiple pregnancy and miscarriage rates (p > 0.05).

CONCLUSIONS

Sequential embryo transfer shows promise in enhancing pregnancy outcomes among RIF patients. However, additional trials are warranted to validate our findings.

Sequential Transfer of Blastocysts on Day 5 and Day 6 in Patients with Repeated Implantation Failure in Frozen Embryo Transfer Cycle

The aim of this study was to evaluate which frozen embryo transfer (FET) strategy benefits the recurrent implantation failure (RIF) population. A retrospective study of 336 women with RIF was performed from July 2020 to October 2023. The patients were divided into three groups according to the FET protocol. The three FET protocols included transferring a blastocyst on both days 5 and 6 (Group 1, n = 138); transferring a cleavage-stage embryo on day 3 and a blastocyst on day 5 (Group 2, n = 55); and transferring double blastocysts on day 5 (Group 3, n = 143).The sequential day 5 and day 6 blastocyst ET strategy significantly improved in vitro fertilization success rates compared with those of both the traditional double-blastocyst day 5 transfer strategy and the strategy involving one cleavage-stage embryo transfer on day 3 and one blastocyst transfer on day 5 in RIF patients. Compared with those observed in Day 5 double-blastocyst transfer, the rates of clinical pregnancy and implantation increased (51.75% vs. 64.49%, P < 0.001 and 37.06% vs. 41.3%, P = 0.005, respectively), while the rates of biochemical pregnancy and multiple gestation decreased (18.18% vs. 12.32%, P = 0.006 and 43.24% vs. 28.09%, P = 0.044, respectively) with the new protocol.Blastocysts from sequential embryo transfer on day 5 and day 6 were more effective than those from the traditional FET protocol at improving pregnancy outcomes and lowering the multiple pregnancy rate in RIF patients. When only one or zero good-quality blastocysts are available, sequential blastocyst ET on days 5 and 6 should be considered.

Effect of sequential embryo transfer on in vitro fertilization and embryo transfer outcomes: a systematic review and meta-analysis

Background

Sequential embryo transfer has been recognized as a strategy to increase pregnancy rates in women undergoing in vitro fertilization and embryo transfer (IVF-ET). However, its impact on assisted reproductive outcomes remains to be substantiated by robust evidence. This systematic review aims to summarize and analyze the available evidence to investigate the effect of sequential embryo transfer on assisted reproductive outcomes.

Methods

A comprehensive literature search was executed across the Pubmed, Cochrane Library, Web of Science, and Scopus databases in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data were aggregated utilizing a random effects model, and the resultant outcomes were articulated as odds ratios (ORs) along with their 95% confidence intervals (CIs).

Results

The pooled results revealed a statistically significant enhancement in reproductive outcomes for infertile patients undergoing sequential embryo transfer as evidenced by elevated rates of chemical pregnancy (OR = 1.67, 95% CI = 1.23-2.27), clinical pregnancy (OR = 1.78, 95% CI = 1.43-2.21), and ongoing pregnancy (OR = 1.54, 95% CI = 1.03-2.31). Compared with cleavage-stage embryo transfer, sequential transfer yielded superior outcomes in terms of chemical pregnancy rate (OR = 2.08, 95% CI = 1.35-3.19) and clinical pregnancy rate (OR = 1.78, 95% CI = 1.37-2.31). Furthermore, among the repeated implantation failure (RIF) cohort, sequential embryo transfer surpassed blastocyst-stage transfer, delivering a heightened chemical pregnancy rate (OR = 1.66, 95% CI = 1.19-2.53) and clinical pregnancy rate (OR = 1.65, 95% CI = 1.19-2.27).

Conclusion

Our meta-analysis indicates that sequential transfer may enhance clinical pregnancy rate in a small subgroup of well-selected women. While promising, further evidence from prospective studies is needed.