Clinical analysis of the patients with single fair cleavage-stage embryo on day 3

Objective: This study aimed to explore an appropriate selection for the patients with single fair cleavage-stage embryo on day 3.Methods: This study included 469 fresh transfers and 220 frozen-thawed transfers from January 2014 to June 2016. Furthermore, in 72 patients who have only 4-6 fair embryos (4-5 blastomeres) on day 3, the blastocysts were cultured to day 5 for transfer.Results: In the fresh transfers, the clinical pregnancy rate of 4-5 blastomeres group was significantly lower than 6-7 and 8-10 blastomeres group (5.88 vs. 30.13%, p<.001and 5.88 vs. 26.09%, p<.001). In the frozen-thawed transfers, the clinical pregnancy rate of 4-5 blastomeres group was also significantly lower than 6-7 and 8-10 blastomeres group (10.00 vs. 28.57%, p=.040 and 10.00 vs. 33.33%, p=.005). For the blastocyst transfers derived from fair embryos with 4-5 blastomeres, the clinical pregnancy rate was significantly higher than single and double fair embryo transfers of similar quality (44.44 vs. 7.04%, p<.001 and 44.44 vs. 28.09%, p=.013).Conclusions: For the patients with single fair embryo (6-7 blastomeres or 8-10 blastomeres), transfer at the cleavage stage is feasible. For the patients with single fair embryo (4-5 blastomeres), transfer of single fair embryo at the blastocyst stage or accumulating two fair embryos might be worthy of consideration.