Purpose

Chronic endometritis (CE) is a frequent hysteroscopic and histological finding which affects embryo transfer implantation during IVF-ICSI cycles. In particular, CE impairs proper decidualization and, subsequently, implantation. Although this correlation has been clearly clarified, a pathophysiological explanation assembling all the studies performed has not been elucidated yet. For this reason, we have structured a systematic review considering all the original articles that evaluated a pathological element involved in CE and implantation impairment.

Methods

The authors searched electronic databases and, after screening, collected 15 original articles. These were fully scanned and used to create a summary pathway.

Results

CE is primarily caused by infections, which lead to a specific cytokine and leukocyte pattern in order to prepare the uterus to fight the noxa. In particular, the immunosuppression requested for a proper semi-allogenic embryo transfer implantation is converted into an immunoreaction, which hampers correct embryo implantation. Moreover, endometrial vascularization is affected and both irregular vessel density and luminal thickening and thrombosis reduce what we have first identified as endometrial flow reserve. Finally, incorrect uterine wave propagation could affect embryo contact with decidua.

Conclusion

This is the first summary of evidence on CE pathophysiology and its relationship with infertility. Understanding the CE pathophysiology could improve our knowledge in embryo transfer success.

中文翻译：

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慢性子宫内膜炎和改变的胚胎植入：从文献系统评价的统一病理生理学理论

目的

慢性子宫内膜炎（CE）是常见的宫腔镜和组织学检查结果，在IVF-ICSI周期中会影响胚胎移植的植入。尤其是，CE损害了适当的蜕膜蜕化，进而损害了植入。尽管已经清楚地阐明了这种相关性，但尚未阐明将所有进行的研究组合在一起的病理生理学解释。因此，我们对所有原始文章进行了系统评价，以评估涉及CE和植入障碍的病理因素。

方法

作者搜索了电子数据库，筛选后收集了15篇原创文章。对这些文件进行了全面扫描，并用于创建摘要路径。

结果

CE主要是由感染引起的，感染会导致特定的细胞因子和白细胞模式，以使子宫做好抵抗诺克素的准备。特别地，将要求适当的半同种异体胚胎移植所需的免疫抑制转化为免疫反应，这妨碍了正确的胚胎植入。此外，子宫内膜血管形成受到影响，不规则的血管密度以及管腔增厚和血栓形成均会降低我们最初确定的子宫内膜血流储备。最后，子宫波传播不正确会影响胚胎与蜕膜的接触。

结论

这是关于CE病理生理及其与不孕症关系的证据的第一个总结。了解CE病理生理学可以提高我们对胚胎移植成功的了解。