Abstract: OBJECTIVE：To observe cleavage patterns of embryos in early stages by time-lapse imaging system，and to evaluate effects of the cleavage patterns on developmental potential of embryos in early stage. METHODS：From January 2019 to July 2021，development of 1 318 embryos cultured with blastocysts which were recorded by the time-lapse imaging system in the reproductive center were retrospectively analyzed. According to the cleavage mode of two prokaryotic (2PN) fertilized eggs，they were divided into normal and abnormal cleavages. Abnormal cleavages included first cleavage anomaly and non-first cleavage anomaly. Pregnancy outcomes such as rates of high-quality embryo， blastocyst formation， high-quality blastocyst， pregnancy， and abortion of early embryos in different cleavage pattern groups were analyzed on day 3. RESULTS： The D3 high-quality embryo rates were 57.36% and 39.47% respectively； blastocyst formation rates were 66.33% and 36.62% respectively； high-quality blastocyst rates were 60.14% and 27.61% respectively in the normal cleavage group and in the abnormal cleavage group. These were significantly higher than those in the abnormal cleavage group (P<0.01). There was no significant difference in clinical pregnancy and miscarriage rates between the normal cleavage and the abnormal cleavage groups(P>0.05). In the abnormal cleavage group，the rates for D3 high-quality embryos and high-quality blastocysts were 34.45% and 24.64% in the first abnormal cleavage group and they were significantly lower than those in the non-first abnormal cleavage group of 58.02% and 37.66% (P<0.05). There was no significant difference in the rates of clinical pregnancy and abortion between the first cleavage anomaly group and the non-first cleavage anomaly group. CONCLUSION：Abnormal cleavage of embryos reduced developmental potential of early embryo. The earlier the abnormal cleavage occurred，the greater the impact on embryonic development.

Key words: time-lapse imaging system, early embryo, cleavage pattern, embryonic development, assisted reproductive technology