Aging endometrium in young women: molecular classification of endometrial aging-based markers in women younger than 35 years with recurrent implantation failure.

BACKGROUND: To explore the differences between a population with premature endometrial aging and a population with normal endometrial status in young women with recurrent implantation failure (< 35 years). METHODS: Systematic analysis of the endometrium transcriptome of 274 RIF women. The NMF algorithm was used for classification based on endometrial-specific aging markers in CellAge, and the endometrial receptivity, gene expression patterns, and clinical data were compared between the classifications. RESULTS: Two hundred forty-five young RIF women could be divided into two clusters, in which the aging gene expression pattern of cluster 2 was closer to the reference cluster. Cluster 1 was characterized by high immune activity, while cluster 2 was characterized by high metabolic activity. Combined with clinical data, cluster 2 was worse than cluster 1 in window of implantation deviation rate and endometrial receptivity. CONCLUSION: Premature aging of the endometrium exists in young women with RIF, and premature aging of the endometrium was associated with poor reproductive outcomes.