Purpose: To observe whether early cleavage can be a predictor of embryo developmental potential, pregnancy and implantation rates.
Methods: A total of 9,544 embryos in 1,095 in vitro fertilization or intracytoplasmic sperm injection cycles were observed with regard to the appearance of early cleavage at 25-29 h post-insemination.
Results: A significantly higher proportion of excellent quality embryos were observed in the early cleavage group compared to the late cleavage group (52.5 versus 28.9%, P < 0.01). In the early cleavage group there was also a higher rate of pregnancy per transfer compared with the late cleavage group (38.7 versus 26.3%, P < 0.01). In addition, we found that transfer of only one early cleavage embryo resulted in a high pregnancy rate (38.5%) and a low multiple pregnancy rate (18.0%).
Conclusion: Early cleavage is a strong indicator of embryo quality, and may be used as an additional criterion in the selection of embryos for transfer to increase pregnancy rate and reduce multiple pregnancy rate.