目的  探讨延时成像监测第二极体（Pb2）释放在预测卵胞质内单精子注射（ICSI）周期卵子受精及胚胎发育效率中的临床应用价值。   方法  回顾性分析278个接受ICSI助孕治疗患者的临床资料和延时成像监测胚胎培养数据，探讨卵子ICSI注射后Pb2释放与否以及具体释放时间与受精及胚胎发育结局的关系。   结果  延时成像监测ICSI注射后Pb2释放平均时间为（3.03±1.21）h；有Pb2释放组的受精率、2原核（2PN）受精率及5d（D5）囊胚转化率均显著高于无Pb2释放组（99.95% vs 1.75%，P<0.001；97.18% vs 0.66%，P<0.001；60.50% vs 16.67%，P<0.05）；Pb2释放时间>3~4 h组2PN受精率显著高于0~2 h组和>5 h组（98.80% vs 93.81%，P<0.05; 98.80% vs 95.40%，P<0.05）；Pb2释放时间与D3胚胎平均卵裂球数显著相关（P<0.001）；>3~4 h组D5囊胚转化率显著低于>2~3 h组（56.23% vs 67.23%，P<0.05），>4~5 h组显著低于0~2 h组、>2~3 h组（46.61% vs 62.30%，P<0.05; 46.61% vs 67.23%，P<0.05），>5 h组D5囊胚转化率为7.14%，均显著低于其他4组（P<0.05）；>3~4 h组D5优质囊胚转化率显著低于0~2 h组、>2~3 h组（9.92% vs 16.39%，P<0.05; 9.92% vs 20.72%，P<0.05），>4~5 h 组显著低于>2~3 h组（11.02% vs 20.72%，P<0.05）。   结论  延时成像监测Pb2释放可以准确预测受精结局，Pb2释放时间与胚胎发育潜力显著相关，是有价值的预测ICSI卵子受精及胚胎发育结局的形态学指标。 

Objective  To explore the clinical value of second polar body (Pb2) exclusion monitoring by time-lapse in predicting the fertilization and embryo development efficiency for intracytoplasmic sperm injection (ICSI).     Methods  A retrospective research was performed on 278 patients treated with ICSI, the clinical data and Time-lapse monitoring embryo culture data were collected and analyzed, to explore the exclusion of Pb2 after ICSI and the relationship between the specific exclusion time and the outcome of fertilization and embryo development.     Results  The average time of Pb2 exclusion after ICSI was (3.03 ± 1.21) hours; The fertilization rate, 2 pronucleus(PN) fertilization rate and 5 days(D5) blastocyst formation rate in the Pb2 exclusion group were significantly higher than those in the without Pb2 exclusion group (99.95% vs 1.75%, P<0.001; 97.18% vs 0.66%, P<0.001; 60.50% vs 16.67%, P<0.05); The 2PN fertilization rate in Pb2 exclusion time >3-4 hours group was significantly higher than that in 0-2 hours group and >5 hours group (98.80% vs 93.81%, P<0.05; 98.80% vs 95.40%, P<0.05); The exclusion time of Pb2 was significantly correlated with the average number of blastomeres in D3 embryos (P<0.001). The D5 blastocyst formation rate of 3-4 hours group was significantly lower than that of >2-3 hours group (56.23% vs 67.23%, P<0.05), >4-5 hours group was significantly lower than 0-2 hours group and >2-3 hours group (46.61% vs 62.30%,  P<0.05; 46.61% vs 67.23%,  P<0.05), and D5 blastocyst formation rate of >5 hours group was 7.14%, which were significantly lower than that of the other four groups ( P<0.05). The formation rate of D5 high-quality blastocysts in 3-4 hours group was significantly lower than 0-2 hours group and > 2-3 hours group (9.92% vs 16.39%,  P<0.05; 9.92% vs 20.72%,  P<0.05), and D5 high-quality blastocysts formation rate in > 4-5 hours group was significantly lower than that in > 2-3 hours group (11.02% vs 20.72%,  P<0.05).     Conclusion  Monitoring Pb2 exclusion by Time-lapse can accurately predict fertilization outcome. The time of Pb2 exclusion is significantly correlated with embryo development potential. It is a valuable morphological index to predict fertilization and embryo development outcome in ICSI.