Dynamic Changes in Endometrial Folding and Secretory Activity Across the Menstrual Cycle
- 1Michigan State University
Abstract
Embryo implantation remains a major limitation of assisted reproductive technology, with failure occurring in approximately 30% of euploid embryo transfers. Implantation requires a synchronized dialogue between the blastocyst and receptive endometrium during the window of implantation (WOI), yet minimally invasive approaches to characterize the structural and molecular features of receptivity remain limited. We analyzed paired sonohysterogram images and uterine lavage samples collected during the proliferative and mid-secretory phases from subjects with regular ovulatory cycles and proven fertility. Endometrial folds were quantified, and lavage samples were analyzed by Luminex multiplex immunoassay. Folds were present in both phases but were significantly more abundant during the mid-secretory WOI, independent of imaging view and endometrial thickness. Folding correlated strongly with circulating estradiol level during the proliferative phase but not the mid-secretory phase, and folding patterns between phases were not correlated, suggesting distinct regulatory mechanisms. Consistent with these structural patterns, uterine lavage demonstrated phase-specific differences in expression of factors associated with endometrial receptivity and implantation, with glandular epithelium, and myeloid-lineage cells emerging as major contributors. Together, these findings identify coordinated structural and secretory processes during the WOI and support further evaluation of endometrial folding and uterine lavage as complementary, minimally invasive markers of endometrial receptivity.
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BibTeX
@misc{paredes2026dynamic,
title = {{Dynamic Changes in Endometrial Folding and Secretory Activity Across the Menstrual Cycle}},
author = {J. G. De Paredes and A. Chemerinski and L. Murali and B. Lynch and Q. Zhao and G. W. Burns and E. Paul and N. Douglas and R. Arora},
howpublished = {bioRxiv},
year = {2026},
month = sep,
doi = {10.64898/2026.09.24.754255},
url = {https://www.biorxiv.org/content/10.64898/2026.09.24.754255v1},
note = {CC BY-NC-ND},
}
RIS
TY - UNPB
TI - Dynamic Changes in Endometrial Folding and Secretory Activity Across the Menstrual Cycle
AU - J. G. De Paredes
AU - A. Chemerinski
AU - L. Murali
AU - B. Lynch
AU - Q. Zhao
AU - G. W. Burns
AU - E. Paul
AU - N. Douglas
AU - R. Arora
PY - 2026
DA - 2026/09/24
PB - bioRxiv
DO - 10.64898/2026.09.24.754255
UR - https://www.biorxiv.org/content/10.64898/2026.09.24.754255v1
AB - Embryo implantation remains a major limitation of assisted reproductive technology, with failure occurring in approximately 30% of euploid embryo transfers. Implantation requires a synchronized dialogue between the blastocyst and receptive endometrium during the window of implantation (WOI), yet minimally invasive approaches to characterize the structural and molecular features of receptivity remain limited. We analyzed paired sonohysterogram images and uterine lavage samples collected during the proliferative and mid-secretory phases from subjects with regular ovulatory cycles and proven fertility. Endometrial folds were quantified, and lavage samples were analyzed by Luminex multiplex immunoassay. Folds were present in both phases but were significantly more abundant during the mid-secretory WOI, independent of imaging view and endometrial thickness. Folding correlated strongly with circulating estradiol level during the proliferative phase but not the mid-secretory phase, and folding patterns between phases were not correlated, suggesting distinct regulatory mechanisms. Consistent with these structural patterns, uterine lavage demonstrated phase-specific differences in expression of factors associated with endometrial receptivity and implantation, with glandular epithelium, and myeloid-lineage cells emerging as major contributors. Together, these findings identify coordinated structural and secretory processes during the WOI and support further evaluation of endometrial folding and uterine lavage as complementary, minimally invasive markers of endometrial receptivity.
ER -