IVF Department, IVIRMA Middle-East Fertility Clinic, Abu Dhabi, United Arab Emirates.
Obstetrical Department, Women´s university hospital Tuebingen, Tuebingen, Germany.
Gynecol Endocrinol. 2020 Jun;36(6):479-483. doi: 10.1080/09513590.2020.1740918. Epub 2020 Mar 18.
The implementation of cryopreservation-techniques in the IVF laboratory and the improved survival rates of oocytes, cleavage and blastocyst stage embryos have led to a significant increase in the number of frozen-thawed embryo transfer cycles (FET). FETs can be planned either in a 'pure' natural cycle, a modified natural cycle, a stimulated cycle or a hormonal replacement therapy cycle and the optimal means to prepare the endometrium for frozen embryo transfer is a topic of ongoing controversy. Recent findings report an increased risk of hypertensive disorders if pregnancy is achieved in a frozen embryo transfer cycle without an existing corpus luteum. Therefore, the question of how to prepare the endometrium has gained even more importance and taken on a new dimension as it should not simply be reduced to the basic question of 'which approach will result in superior pregnancy rates?' but instead 'which approach will result in the best pregnancy rates and the safest outcome for mother and baby?'. The aim of this review is to summarize and critically appraise the existing data on the different approaches of endometrial preparation for frozen embryo transfer with a special focus on the 'pure' natural cycle.
在 IVF 实验室中实施的冷冻保存技术以及卵母细胞、卵裂期和囊胚期胚胎存活率的提高，导致了冷冻胚胎移植周期（FET）数量的显著增加。FET 可以在“纯”自然周期、改良自然周期、刺激周期或激素替代治疗周期中进行计划，为冷冻胚胎移植准备子宫内膜的最佳方法是一个持续存在争议的话题。最近的研究结果报告称，如果在没有黄体的情况下通过冷冻胚胎移植周期怀孕，患高血压疾病的风险会增加。因此，如何准备子宫内膜的问题变得更加重要，并呈现出一个新的维度，因为它不应该简单地归结为“哪种方法会导致更高的怀孕率？”而是“哪种方法会导致最佳的怀孕率和母婴最安全的结果？”。本文综述的目的是总结和批判性地评价冷冻胚胎移植中不同的子宫内膜准备方法的现有数据，特别关注“纯”自然周期。
