The Impact of Cleavage and Blastocyst Stage Sequential Transfer on Clinical Pregnancy Outcomes of Frozen Embryo Transfer in Patients with Multiple Transplant Failures: A Retrospective Cohort Study.

BACKGROUND

To assess sequential embryo transfer's impact on clinical outcomes in frozen embryo transfer (FET) cycles for patients with multiple transfer failures.

METHODS

This retrospective cohort study encompasses 4,499 FET cycles involving double embryo transfers conducted at the Reproductive Medicine Center of Nanjing Drum Tower Hospital from 2020 to 2023. Group analyses were performed based on the type of transferred embryos (cleavage-stage embryos, blastocysts, and sequential embryo transfers) to assess the correlation between sequential transfers and clinical pregnancy rates, live birth rates, and multiple pregnancy rates. Subgroup analysis focused on patients with >3 prior failures. Multivariate logistic regression adjusted for confounders.

RESULTS

Sequential transfer did not improve clinical pregnancy (aOR = 0.94, 95% CI: 0.67-1.32, p = 0.73) or live birth rates (aOR = 0.90, 95% CI: 0.65-1.23, p = 0.49) versus blastocyst transfer, but significantly reduced multiple pregnancies (aOR = 0.50, 95% CI: 0.34-0.75, p = 0.0008). Among patients with multiple failures, sequential transfer showed no significant association with clinical pregnancy (aOR = 0.57, 95% CI: 0.29-1.11, p = 0.09) or live birth rates (aOR = 0.94, 95% CI: 0.49-1.81, p = 0.85), yet significantly lowered multiple pregnancy odds (aOR = 0.30, 95% CI: 0.10-0.90, p = 0.03).

CONCLUSION

Sequential embryo transfer does not enhance clinical pregnancy or live birth rates in FET cycles, regardless of prior failure history, but effectively reduces multiple pregnancy rates. For patients with >3 embryo transfer failures, it yields live birth rates comparable to blastocyst transfer, representing a potentially advantageous option for this population.