Reproductive Medicine Center, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, PR China.
Reprod Biomed Online. 2013 Aug;27(2):154-60. doi: 10.1016/j.rbmo.2013.04.006. Epub 2013 Apr 19.
Surplus embryos available for cryopreservation in fresh cycles are considered as having good potential for future use. However, the optimal stage of embryo cryopreservation remains unclear. In this study, 1190 patients with surplus embryos on day 3 were divided into two groups: cleavage-stage embryo cryopreservation (control group) and blastocyst cryopreservation (blastocyst group). The clinical outcomes of the subsequent warming cycles were evaluated. The proportion of cycles with blastocyst formation was 73.8% in the blastocyst group. Although in the blastocyst group, the cancellation rate of blastocyst transfer was increased due to lack of blastocysts available for cryopreservation, the blastocyst group achieved significantly higher rates of clinical pregnancy/cycle (43.2% versus 34.9%; P=0.003), pregnancy/transfer (59.5% versus 35.4%; P<0.001) and implantation (46.5% versus 22.2%; P<0.001) from the first warming cycle compared with the control group. In an embryo-number classified analysis, the clinical pregnancy rate was also higher in the blastocyst group. However, the cumulative pregnancy was similar between the two groups. Blastocyst culture as an embryo selection tool will not improve embryo viability but it will help patients to achieve pregnancy more quickly. Extended culture of surplus embryos to the blastocyst stage for cryopreservation optimizes the clinical outcomes.
在新鲜周期中可用于冷冻保存的多余胚胎被认为具有良好的未来使用潜力。然而，胚胎冷冻保存的最佳阶段仍不清楚。本研究将 1190 例第 3 天有多余胚胎的患者分为两组：卵裂期胚胎冷冻保存（对照组）和囊胚冷冻保存（囊胚组）。评估了随后的解冻周期的临床结局。囊胚组囊胚形成率为 73.8%。尽管囊胚组由于缺乏可用于冷冻保存的囊胚，取消囊胚转移的比例增加，但囊胚组在第一次解冻周期中实现了显著更高的临床妊娠/周期率（43.2%对 34.9%；P=0.003）、妊娠/移植率（59.5%对 35.4%；P<0.001）和着床率（46.5%对 22.2%；P<0.001），明显高于对照组。在胚胎数量分类分析中，囊胚组的临床妊娠率也更高。然而，两组的累积妊娠率相似。囊胚培养作为胚胎选择工具不会提高胚胎活力，但它将帮助患者更快地实现妊娠。将多余胚胎延长培养至囊胚阶段进行冷冻保存可以优化临床结局。
