The precise determination of the window of implantation significantly improves ART outcomes

M Enciso,E Pérez-Larrea,M Ferrández-Rives,I Jurado,K Marron,E Rodríguez,J Sarasa,J Aizpurua,A B Climent,B Rodríguez-Estrada

doi:10.1038/s41598-021-92955-w

Abstract

The human endometrium is receptive to the embryo for a specific period of time known as the window of implantation (WOI). During this period, the endometrium shows a specific gene expression profile suitable for endometrial function evaluation. ER Map is a molecular tool able to accurately predict endometrial receptivity status by transcriptomic analysis. In this retrospective study, including 2256 subfertile patients undergoing ART treatment, the clinical value of precise WOI determination is studied in detail. Results obtained when single embryo transfers (sET) were scheduled either within the WOI timeframe as established by ER Map, or deviating from this WOI, are assessed and compared. Data obtained showed that 34.18% (771/2256) of patients had a displaced WOI. Analysis of ART outcomes showed significantly higher pregnancy rates in transfers scheduled within the WOI predicted compared to transfers that deviated more than 12h from this WOI (44.35% vs 23.08%, p < 0.001). The deviation from the WOI had also an impact on the progression of pregnancy, with a significant increase in pregnancy loss (~ twofold) observed in transfers that deviated more than 12h from the WOI predicted. These results indicate that the precise determination of the WOI and personalised embryo transfer can significantly improve clinical outcomes.

Highlights

One of the key processes for the establishment of a successful pregnancy is embryonic implantation into the endometrium, the mucous tissue that lines the inside of the uterus
The human endometrium undergoes important structural and functional changes in order to reach a status optimum for embryonic implantation. This period of time where the endometrium is receptive to the embryo is called the window of implantation (WOI) and it usually occurs between days 19 and 21 of the cycle[5,6]
We present results from the application of Endometrial Receptivity Map (ER Map) in the clinical setting in order to assess the efficacy of this tool for the precise determination of the WOI, the identification of cases of WOI displacement and the improvement of clinical outcomes following embryo transfer according to ER Map recommendation

Summary

Introduction

One of the key processes for the establishment of a successful pregnancy is embryonic implantation into the endometrium, the mucous tissue that lines the inside of the uterus. The human endometrium undergoes important structural and functional changes in order to reach a status optimum for embryonic implantation. This period of time where the endometrium is receptive to the embryo is called the window of implantation (WOI) and it usually occurs between days 19 and 21 of the cycle[5,6]. ER Map, a molecular tool for human endometrial receptivity evaluation based on the transcriptomic analysis of genes related to endometrial proliferation and embryonic implantation has been developed. We present results from the application of ER Map in the clinical setting in order to assess the efficacy of this tool for the precise determination of the WOI, the identification of cases of WOI displacement and the improvement of clinical outcomes following embryo transfer according to ER Map recommendation

Methods

Results

Conclusion