Relationship Between Morphology, Euploidy and Implantation Potential of Cleavage and Blastocyst Stage Embryos

Aim: The aim of this study was to investigate the relationship between the morphology, euploidy and implantation rate of cleavage stage and blastocyst stage embryos.

Setting: Institution-based, tertiary care fertilization centre.

Study Design: This study included a retrospective data analysis of 306 embryos: 154 cleavage stage embryos and 152 blastocysts that underwent biopsy on day 3 and day 5/6, respectively, which were subsequently screened for aneuploidy by array comparative genomic hybridization analysis.

Materials And Methods: Both cleavage stage and blastocyst stage embryos were categorized according to their morphology into the following three groups: good, average and poor. In addition, blastocysts were categorized into day 5 and day 6 embryos on the basis of their developmental rate.

Results: The euploidy rate was found to be significantly higher for blastocysts with good morphology as compared to those with poor morphology, with 73.2, 50 and 40.5% euploid embryos in the good, average and poor morphology groups, respectively ( = 0.001). No significant association was found between day 3 embryo morphology and euploidy rates with 40.6, 29.3 and 25.8% euploid embryos in the three groups, respectively ( = 0.254). The implantation rates, as per morphology, for the transferred euploid cleavage stage and blastocyst stage embryos were 43.8, 37.5 and 0% ( = 0.354) and 51.7, 71.4 and 66.7% ( = 0.562) in the good, average and poor morphology groups, respectively. The euploidy rate for day 5 blastocysts was significantly higher (70% vs. 34.1%, < 0.001) than that of day 6 blastocysts, but the implantation rate was similar in both the groups (58.8 and 50%, respectively). The miscarriage rates for the euploid cleavage stage and the blastocysts stage embryos were 18.2 and 8.3% ( = 0.575), respectively.

Conclusion: Blastocyst morphology and the rate of development were found to be significantly associated with euploidy, whereas cleavage stage morphology was not. The implantation rates of the good quality, euploid cleavage stage embryos were higher than that of the poor quality embryos. The implantation rates were similar for all transferred euploid blastocysts, irrespective of their morphology or the rate of development.