IFFS/JSRM International Meeting 2015(2015.4.26-29 Yokohama）

The nuclear status of Day2 embryo effects to blastocyst formation rate.

• Objective

  We investigated the good quality blastocyst formation rate on day5 depend on the nuclear status of Day2 embryo.

• Materials and Methods

  In this study, we retrospectively reviewed 137 IVF cycles from May 2008 to July 2014 in our clinic. The total of 439 embryos were classified on Day2 in accordance with nuclear status including the number of nuclei in each blastomere and the number of blastomere with at least one nucleus. Four groups were constituted according to the embryo nucleus: group1: embryos with at least one multinucleated blastomere (MNB) (n=59); group2: embryos invisible nuclei in all blastomeres (n=110); group3: embryos having one or more mononucleated blastomeres without any MNB (n=140); group4: embryos having all mononucleated blastomeres (n=130). Four groups were compared with the good quality blastocyst formation rate.

• Results

  A total of 121 (27.6%) embryos formed good quality blastocysts on day5. Group4 was significantly higher than other groups for the good quality blastocyst formation rate (31.6%; group1, 46.9%; group2, 47.9%; group3 vs. 69.5%; group4; p<0.05).

• Conclusions

  Day2 embryos which have all mononucleated blastomeres are highly possible to be good quality blastocysts.