Origen, Centro de Medicina Reprodutiva, Brazil.
Cryobiology. 2012 Dec;65(3):332-4. doi: 10.1016/j.cryobiol.2012.05.012. Epub 2012 Jun 19.
The role of cryopreservation in assisted reproductive technology programs has increased within the last years allowing the transfer of a limited number of embryos and the storage of the remaining for future use. The reduction in the number of transferred embryos decreases the frequency of multiple pregnancy rates and of ovarian hyperstimulation syndrome while the cumulative pregnancy rate can be maximized. Moreover, as not all embryos will survive the warming process more cleavage stage embryos are warmed to improve selection for transfer. Therefore, surplus good quality cleavage stage embryos and/or blastocysts must be re-vitrified for further transfer to achieve pregnancy. To our knowledge, there have been no reports demonstrating that human embryos can be successfully vitrified/warmed twice at the cleavage stage. Thus we report two successful pregnancies and deliveries of healthy babies after transfer of embryos that were twice vitrified/warmed at 2-4 cells stage.
在过去的几年中，冷冻保存技术在辅助生殖技术项目中的作用不断增强，使得能够转移有限数量的胚胎，并储存剩余的胚胎以备将来使用。减少转移胚胎的数量可以降低多胎妊娠率和卵巢过度刺激综合征的发生率，同时最大限度地提高累积妊娠率。此外，由于并非所有胚胎都能在解冻过程中存活，因此需要解冻更多的卵裂期胚胎，以提高选择用于转移的胚胎的质量。因此，必须将多余的优质卵裂期胚胎和/或囊胚重新玻璃化，以便进一步转移以实现妊娠。据我们所知，目前还没有报道表明人类胚胎可以在卵裂期成功进行两次玻璃化/解冻。因此，我们报告了两例成功的妊娠和分娩，这些婴儿是在两次玻璃化/解冻的 2-4 细胞阶段后转移胚胎的。
