摘要目的:探讨第3日（D3）4~5-细胞I、II及III级胚胎（4/I~5/III）囊胚的形成及移植对体外受精-胚胎移植（IVF-ET）临床结局的影响。方法:回顾性分析2016年1月至2019年2月期间在解放军联勤保障部队第901医院采用IVF-ET助孕患者共884个周期的临床资料。比较4/I~5/III组间囊胚形成差异；根据囊胚移植周期中D3卵裂胚的情况，将4/I~5/III胚胎来源的164个囊胚移植周期设为A组，247个优质胚胎来源的囊胚移植周期设为B组，比较两组间的临床结局并分析4/I~5/III组间不同细胞数和评级对临床妊娠率及流产率的影响。结果:4/I组的优质囊胚率（5.6%）高于4/II组（1.8%）（ P=0.003）及4/III组（0.6%）（ P<0.001）；5/I组优质囊胚率（8.3%）分别高于4/II组、4/III组及5/III组（1.6%）( P均<0.001)；5/II组优质囊胚率（8.4%）高于4/III组( P<0.001)。A组与B组在获卵数、成熟卵数、受精率、卵裂率、移植胚胎数、移植优质囊胚比、临床妊娠率、流产率、种植率及持续妊娠率差异均无统计学意义（ P>0.05）；A组D3优质胚胎率显著低于B组( P<0.001)；A组平均移植周期次数高于B组（ P=0.034）；4-细胞和5-细胞来源的囊胚移植临床妊娠率分别为51.6%和50.0%，流产率分别为15.2%和26.8%；I+II级与III级胚胎来源的囊胚移植临床妊娠率分别为53.6%和41.2%，流产率分别为22.4%和21.4%，组间差异均无统计学意义（ P>0.05）。 结论:4/I~5/III来源的囊胚能够获得与优质卵裂胚来源囊胚相近的临床结局；在4/I~5/III组间，细胞数和评级不会影响其囊胚的临床妊娠率及流产率，但5-细胞胚胎的囊胚形成率高于4-细胞胚胎。

abstractsObjective:To investigate the effects of blastulation and transferred blastocyst derived from the 4-5-cell grade I to III (4/I-5/III) embryos on day 3 on clinical outcomes of in vitro fertilization and embryo transfer (IVF-ET). Methods:A total of 884 IVF cycles with blastocyst culture in the 901st Hospital of the Joint Logistics Support Force of PLA from January 2016 to February 2019 were retrospectively analyzed. The blastocyst formation status was compared among the 4/I-5/III embryos. Blastocyst derived from 4/I-5/III embryos in transfer cycle was served as group A ( n=164), blastocyst derived from good-quality cleavage stage embryos (7/I-10/II) in transfer cycle was served as group B ( n=247) according to quality of cleavage stage embryos on day 3. The clinical outcomes were compared between the two groups. The effects of different blastomere number and grade on clinical pregnancy rate and spontaneous abortion rate were evaluated among the 4/I-5/III embryos. Results:Good-quality blastulation rate for 4/I, 4/II, 4/III, 5/I, 5/II and 5/III were 5.6%, 1.8%, 0.6%, 8.3%, 8.4% and 1.6%, respectively. The differences reached statistical significances ( P<0.05). There were no significant differences in number of oocytes retrieved, number of mature oocytes, fertilization rate, cleavage rate, number of transferred embryos, percentage of good-quality blastocyst transfer cycles, clinical pregnancy rate, spontaneous abortion rate, implantation rate and ongoing pregnancy rate between group A and group B ( P>0.05), group A had higher number of embryo transfer cycles ( P=0.034) and lower good-quality embryo rate on day 3 ( P<0.001). There were no significant differences in clinical pregnancy rate and spontaneous abortion rate between transferred blastocyst derived from the 4-cell and 5-cell embryo (51.6% vs. 50.0%；15.2% vs. 26.8%, respectively). There were no significant differences in clinical pregnancy rate and spontaneous abortion rate between transferred blastocyst derived from grade I+II and grade III (4/I-5/III) (53.6% vs. 41.2%； 22.4% vs. 21.4%, respectively). Conclusion:Blastocyst derived from 4/I-5/III embryos and good cleavage stage embryos both are similar clinical outcomes in blastocyst transfer cycles, there are no effects of blastomere number and grade on clinical pregnancy rate and abortion rate in blastocyst transfer cycles, but blastulation rate derived from 5-cell embryo was significantly higher than that of 4-cell embryo.