Clin Exp Reprod Med.  2023 Mar;50(1):63-68. 10.5653/cerm.2022.05540.

The pregnancy outcomes of day-5 poor-quality and day-6 high-quality blastocysts in single blastocyst transfer cycles

• Zhang Gl
• Sun Ty
• Li S
• Jiang Mx
• Guo L

• KMID: 2540248
• DOI: http://doi.org/10.5653/cerm.2022.05540

Abstract

Objective
This study compared the outcomes of single blastocyst transfer cycles, using day- 5 poor-quality blastocysts and day-6 high-quality blastocysts.
Methods
We analyzed 462 frozen-thawed embryo transfer (FET) cycles performed at our center from January 2014 to December 2019. The cycles were divided into two groups: a day-5 poor-quality blastocyst transfer group (group A) and a day-6 high-quality blastocyst transfer group (group B). The clinical outcomes were tested.
Results
In groups A and B, respectively, the clinical pregnancy rate (CPR; 61.65% vs. 67.17%, p=0.258), implantation rate (IR; 61.65% vs. 67.17%, p=0.258), and live birth rate (LBR; 69.51% vs. 77.83%, p=0.134) showed no significant differences. Moreover, when day-3 embryo quality was considered, the CPR, IR, and LBR were also similar in group A and group B (p>0.05).
Conclusion
The clinical outcomes of day-5 poor-quality blastocysts and day-6 high-quality blastocysts were similar, suggesting that the developmental speed of the embryo might be more important than embryo quality for the clinical outcomes of single blastocyst transfer in FET cycles.

Keyword

Blastocyst; Developmental speed; Embryo quality; Frozen-thawed embryo transfer