Relationship between blastomere damage of thawed embryos and embryonic development potential

Objective: To explore whether blastomere damage affects the ability of embryonic development in frozen-thawed embryo transfer (FET) cycles and to provide practical basis for selection of suitable embryos for transfer. Methods: The clinical FET cases from Reproductive Medicine Center, Department of Gynecology & Obstetrics, Xijing Hospital of Fourth Military Medical University, between January 2010 and December 2011, were analyzed retrospectively. According to the integrity of blastomeres of transfer embryo after resuscitation, the cases were divided into integrity group (group A): the number of blastomeres of thawed embryos was more than 4 and the fragments were less than 15% (n=214); partial damage group (group B): there were 1-2 damaged blastomeres within the thawed embryos and at least 6 complete blastomeres, and the fragments were less than 15% (n=62). Differences in quantitative data were compared with t test. Enumeration data were compared with χ² test and logistic regression analysis. Results: There were no significant differences in maternal age, body mass index, the average endometrial thickness, and the number of embryos per cycle between group A and group B (P>0.05). The implantation rate and pregnancy rate were higher in group A than in group B while the abortion rate was lower in group A than in group B, with significant differences (P=0.047). Logistic regression analysis indicated that there was still a significantly negative correlation between blastomeres damage and clinical pregnancy outcomes after adjusting for the confounding factors (P<0.05). Conclusion: Embryonic blastomeres damage can affect the potential of embryo development in the thawed embryo transfer cycles.