Day 3 embryo quality impact on euploidy rate and pregnancy outcomes: a retrospective study of 12,669 PGT-A embryos.

RESEARCH QUESTION: Is there any difference in euploidy rate and outcomes between blastocysts derived from poor- and good-quality day 3 embryos?

DESIGN

This retrospective cohort study included a total of 1492 preimplantation genetic testing for aneuploidies cycles with 12,669 day 3 embryos. These were divided into good- and poor-quality groups based on the morphological quality on day 3. The study compared the blastocyst formation rates between the two groups, as well as the euploidy rate of the blastocysts and the pregnancy outcomes after transferring the euploid blastocysts.

RESULTS

The blastocyst formation rate was significantly higher in the day 3 good-quality group compared with the day 3 poor-quality group (53.6% versus 19.3%, P < 0.001). There was no significant difference in the blastocyst euploidy rate between the two groups (43.8% versus 42.6%, P = 0.150). When euploid blastocysts were transferred, a significant difference was observed in the biochemical pregnancy rate between the two groups (68.8% versus 76.3%, P = 0.028), while no significant differences were found in the clinical pregnancy rate (61.4% versus 66.7%, P = 0.143), miscarriage rate (15.1% versus 18.4%, P = 0.317), ectopic pregnancy rate (0.5% versus 0.0%, P = 0.587) and live birth rate (51.4% versus 53.5%, P = 0.562).

CONCLUSIONS

Day 3 embryo quality significantly influenced blastocyst formation rate, but did not affect either blastocyst euploidy or pregnancy outcomes. This indicates that once embryos can develop into transferrable blastocysts, their quality may be considered to be of a comparable level regardless of the morphology of their cleavage stage.