The Blastulation Rate Is Negatively Associated With Euploid Rate.

OBJECTIVES

To study the association between the blastulation rate, the presence of 1 pronucleus (1PN) zygotes, and the ploidy of the cohort of blastocysts.

METHODS

A cross-sectional study using the existing databases of 2 university fertility centres in Canada. We included 345 cycles from 235 couples who underwent next-generation sequencing preimplantation genetic testing for the detection of aneuploidy in the study.

RESULTS

A total of 1456 blastocysts were biopsied. In multivariate analysis, only female age and the number of 1PN/2PN embryos showed a negative association with euploid ratio. Surprisingly, when the analysis was limited to cycles with no delayed blastulation, the blastulation rate was also negatively associated with the euploid ratio.

CONCLUSIONS

This study sheds some light on the stages of early embryo development. Further study on the mechanisms governing embryo development and the different cell cycle checkpoints in embryo development is warranted.