# Precise hourly personalized embryo transfer significantly improves clinical outcomes in patients with repeated implantation failure

## TL;DR

A new test that identifies the best time for embryo transfer improves pregnancy chances in patients with repeated implantation failure.

## Contribution

The study shows that precise timing of embryo transfer based on RNA-Seq improves clinical outcomes in patients with repeated implantation failure.

## Key findings

- Patients using rsERT had higher clinical pregnancy rates (54.8%) compared to standard FET (38.6%).
- Non-receptive rsERT patients had significantly better pregnancy outcomes than FET patients.
- Precise timing of embryo transfer improved success rates, especially in non-receptive cases.

## Abstract

This study investigated whether RNA-Seq-based endometrial receptivity test (rsERT)—which provides precision for the optimal hour of the window of implantation (WOI)—can improve clinical outcomes of frozen embryo transfer (FET) cycles in patients with a history of repeated implantation failure (RIF).

Patients with a history of RIF who received at least one autologous high-quality blastocyst during the subsequent FET cycle were retrospectively enrolled and divided into two groups: rsERT and FET, comprising patients who underwent rsERT-guided pET (n=115) and standard FET without rsERT (n=272), respectively.

In the rsERT group, 39.1% (45/115) of patients were receptive. rsERT patients showed a higher probability of achieving both positive human chorionic gonadotropin (63.5% vs. 51.5%, P=0.03) and clinical pregnancy (54.8% vs. 38.6%, P=0.003) rates. In subgroup analysis, rsERT patients with non-receptive results had higher clinical pregnancy rates than patients undergoing FET (58.6% vs. 38.6%, P=0.003). rsERT patients with receptive results guided by rsERT with a precise WOI time had higher, although non-significant, clinical pregnancy rates (48.9% vs. 38.6%, P=0.192) than patients who underwent standard-time FET.

Hourly precise rsERT can significantly improve the probability of achieving clinical pregnancy in patients with RIF, especially in those with non-receptive rsERT results.