Advanced maternal age as a risk factor for endometrial receptivity in repeated implantation failure: intersectional...

Repeated implantation failure (RIF) remains a significant challenge in assisted reproductive technology. Endometrial receptivity (ER) plays a critical role in embryo implantation. However, the impact of advanced maternal age (AMA) on ER in this population remains unclear. The study aimed to evaluate whether maternal age is associated with displacement of the window of implantation (WOI) and explore potential endometrial transcriptomic characteristics.

This retrospective observational study included 254 women with RIF who underwent evaluation of ER between January 2020 and March 2024. ER status and WOI timing were determined using a transcriptome-based receptivity assessment. Clinical characteristics were compared between women with normal receptivity and those with a 2-day pre-receptive endometrium. Endometrial biopsies were analyzed by RNA sequencing to identify differential gene expression associated with age and receptivity status. An independent small validation cohort was used for qRT-PCR validation.

Women in the impaired receptivity group (2-day pre-receptive) were significantly older than those in the normal receptivity group (34.3 ± 3.1 vs. 33.0 ± 4.1, p = 0.016). Multivariate logistic regression further demonstrated maternal age as an independent risk factor for ER displacement (OR = 1.118, 95% CI: 1.013-1.234, p = 0.027). Transcriptomic analysis identified age- and receptivity-associated transcriptomic changes, with 10 overlapping differentially expressed genes (DEGs) between the two comparisons, which were further examined by qRT-PCR in a small independent cohort (n = 10). As a result, four genes, including activating transcription factor 3 (ATF3), C-X-C motif chemokine ligand 1 (CXCL1), parathyroid hormone-like hormone (PTHLH), and non-specific cytotoxic cell receptor protein 1 (NCCRP1), were significantly downregulated in the AMA-RIF group compared with controls.

AMA was independently associated with an increased likelihood of WOI displacement in women with RIF, suggesting that aberrant endometrial timing may be associated with implantation failure in this population. These findings provide a rationale for further investigation of personalized embryo transfer strategies in older patients, while the identified candidate genes should be regarded as preliminary molecular associations requiring further functional validation.