OBJECTIVETo explore the effects of different fertilization methods on the outcomes of elective blastocyst culture.

METHODSWe retrospectively analyzed the outcomes of elective blastocyst culture for 1 153 cycles of IVF and 205 cycles of ICSI performed between january 2009 and December 2012.

RESULTSA total number of 14 748 embryos in the IVF group and 2 655 embryos in the ICSI group underwent sequential blastocyst culture, with 7 871 blastocysts formed in the former and 1 210 in the latter. No cycles were canceled for no blastocyst formation in either of the two groups. The rates of quality embryos, blastocyst formation and embryo utilization were significantly higher in the IVF than in the ICSI group (64.77 vs 58.72%, 53.37 vs 45.57%, and 60.06 vs 52.17%, all P < 0.05), but the rates of implantation, clinical pregnancy and abortion showed no significant differences between the two groups (48.94 vs 51.43%, 49.03 vs 52.02%, and 11.69% vs 15.56, all P > 0.05).

CONCLUSIONWith the same inclusion criteria of selective blastocyst culture, IVF has a lower risk of cycle cancellation due to no blastocyst formation and therefore may effect higher rates of blastocyst formation and embryo utilization than ICSI. Our study suggested that appropriate inclusion criteria of selective blastocyst culture should be laid down according to different fertilization methods.