Uterine Biology, Prince Henry's Institute of Medical Research, Clayton, VIC 3168, Australia Department of Physiology, Monash University, Clayton, VIC 3168, Australia.
Uterine Biology, Prince Henry's Institute of Medical Research, Clayton, VIC 3168, Australia Department of Obstetrics and Gynaecology, University of Melbourne, Heidelberg, VIC 3084, Australia.
Hum Reprod Update. 2014 Nov-Dec;20(6):808-21. doi: 10.1093/humupd/dmu027. Epub 2014 Jun 10.
Improvements in vitrification now make frozen embryo transfers (FETs) a viable alternative to fresh embryo transfer, with reports from observational studies and randomized controlled trials suggesting that: (i) the endometrium in stimulated cycles is not optimally prepared for implantation; (ii) pregnancy rates are increased following FET and (iii) perinatal outcomes are less affected after FET.
This review integrates and discusses the available clinical and scientific evidence supporting embryo transfer in a natural cycle.
Laboratory-based studies demonstrate morphological and molecular changes to the endometrium and reduced responsiveness of the endometrium to hCG, resulting from controlled ovarian stimulation. The literature demonstrates reduced endometrial receptivity in controlled ovarian stimulation cycles and supports the clinical observations that FET reduces the risk of ovarian hyperstimulation syndrome and improves outcomes for both the mother and baby.
This review provides the basis for an evidence-based approach towards changes in routine IVF, which may ultimately result in higher delivery rates of healthier term babies.
玻璃化技术的进步使得冷冻胚胎移植（FET）成为新鲜胚胎移植的可行替代方案，观察性研究和随机对照试验的报告表明：（i） 促排卵周期中的子宫内膜对着床的准备并不理想；（ii）FET 后妊娠率增加；（iii）FET 后围产期结局受影响较小。
本综述综合并讨论了支持自然周期胚胎移植的现有临床和科学证据。
基于实验室的研究表明，控制性卵巢刺激会导致子宫内膜形态和分子发生变化，以及子宫内膜对 hCG 的反应性降低。文献表明控制性卵巢刺激周期中子宫内膜容受性降低，并支持 FET 降低卵巢过度刺激综合征风险和改善母婴结局的临床观察。
本综述为 IVF 常规改变提供了循证依据，最终可能会提高更健康足月婴儿的分娩率。
