Abstract

Background: The ‘freeze-all’ practice refers to the cryopreservation of all mature oocytes or viable embryos after ovarian stimulation. The development of the vitrification technique has been crucial to make this approach a reality, since it increases the post-thaw survival rates and permits comparable implantation rates with fresh embryos. Nonetheless, as implantation probabilities are comparable to fresh embryo transfer in normo-responder patients, the freeze- all strategy has demonstrated no benefits overall.

Method: Narrative review in which we give an overview of this approach, discuss recent advances in the field, as well as for whom, when and how it is recommended to emply the freeze-all technique.

Results: However, there is some clinical evidence that shows its feasibility. Thus, it has been demonstrated that elevation of progesterone at the end of ovarian stimulation decreases the implantation rates after the transfer of day 6 blastocysts in fresh and some uterine pathologies; freeze-all is also the preferred option for patients undergoing pre-implantation genetic testing, since there is an improvement of the results and it allows for inclusion of all blastocysts of the cohort. In high responders, the freeze-all strategy optimizes the response whilst also minimizing the risk of ovarian hyperstimulation syndrome.

Conclusion: Due to the different cases that a reproductive expert might encounter, it is essential to highlight benefits and drawbacks of this practice.

摘要

背景： “全冷冻”实践是指在卵巢刺激后冷冻保存所有成熟卵母细胞或有生命的胚胎。玻璃化技术的发展对于使这种方法成为现实至关重要，因为它提高了解冻后的存活率并允许与新鲜胚胎相媲美的植入率。但是，由于正常反应患者的植入概率与新鲜胚胎移植的效果相当，因此冻结全策略并未显示出整体益处。

方法：叙述性综述，其中我们概述了这种方法，讨论了该领域的最新进展，以及针对谁，何时以及如何建议采用全冷冻技术。

结果：但是，有一些临床证据表明了其可行性。因此，已经证明卵巢刺激结束时黄体酮的升高降低了新鲜和某些子宫病变中第6天囊胚转移后的着床率。对于进行植入前基因测试的患者，fall-all也是首选的选择，因为结果有所改善，并且可以纳入该队列的所有胚泡。在高反应者中，全冷冻策略可优化反应，同时还将卵巢过度刺激综合征的风险降至最低。

结论：由于生殖专家可能会遇到不同的情况，因此必须强调这种做法的利弊。