目的:探讨体外受精(IVF)周期中胚胎细胞数量和碎片比例对囊胚形成的影响。方法:回顾性分析2 404个IVF周期患者的13 037个进行囊胚培养的胚胎。根据第3日细胞数量将胚胎分为2~3-细胞组(2C~3C)、4-细胞组(4C)、5-细胞组(5C)、6-细胞组(6C)、7-细胞组(7C)、8-细胞组(8C)、9-细胞组(9C)、10-细胞组(10C)、11-细胞组(11C)、12-细胞组(12C)、≥13-细胞组(≥13C),分析囊胚培养细胞数量和碎片比例与囊胚形成的关系。结果:碎片为1~2级的胚胎,8C组和≥13C组囊胚形成率明显高于其他各组(P<0.05);7C、9C~12C组之间囊胚形成率无统计学差异(P>0.05)。碎片为3级的胚胎,8C组的囊胚形成率高于其他各组(P<0.05),且与碎片1~2级7C、9C~12C组的胚胎相比无统计学差异(P>0.05);9C组囊胚形成率高于7C组,且差异显著(P<0.05)。结论:第3日8C胚胎的发育潜能是最优的,可适当放宽对8C碎片的评估;随着碎片比例增大可减弱胚胎的发育潜能。 Objective: To investigate the effect of embryo cell number and fragment ratio on the formation of blastocysts during in vitro fertilization (IVF) cycles. METHODS: A total of 13 037 embryos cultured in blastocysts from 2 404 IVF patients were retrospectively analyzed. The embryos were divided into 2-3 cell groups (2C ~ 3C), 4-cell group (4C), 5-cell group (5C), 6-cell group (7C), 8-cell group (8C), 9-cell group (9C), 10- cell group (10C), 11- cell group (11C), 12- cell group ≥13C), analyzed blastocyst culture cell number and the proportion of fragments and the relationship between blastocyst formation. Results: The blastocyst formation rate was significantly higher in the groups of 1 ~ 2 embryos than in the other groups (P <0.05). There was no significant difference in the blastocyst formation rate between the 7C, 9C ~ 12C groups P> 0.05). The blastocyst formation rate of 8C group was higher than that of other groups (P <0.05), and there was no significant difference between embryos of 7C and 9C ~ 12C groups of 1 ~ 2 grade (P> 0.05) ). The blastocyst formation rate in group 9C was higher than that in group 7C (P <0.05). Conclusion: The developmental potential of 8C embryos on Day 3 is optimal, and the evaluation of 8C fragments can be appropriately relaxed. The developmental potential of embryos can be weakened as the proportion of fragments increases.