The endometrial receptivity array for diagnosis and personalized embryo transfer as a treatment for patients with repeated implantation failure.

Objective: To demonstrate the clinical value of the endometrial receptivity array (ERA) in patients with repeated implantation failure (RIF), for guiding their personalized embryo transfer (pET) as a novel therapeutic strategy.

Design: Prospective interventional multicenter clinical trial.

Setting: University-affiliated infertility and private clinics.

Patient(s): Eighty-five RIF patients and 25 comparison patients.

Intervention(s): Endometrial sampling and pET guided by ERA.

Main Outcome Measure(s): A receptive (R) or nonreceptive (NR) endometrial status according to ERA. Pregnancy (PR) and implantation (IR) rates after pET.

Result(s): The ERA test gave an R result of 74.1% in RIF patients versus 88% in control subjects. Clinical follow-up was possible in 29 RIF patients, in whom pET was performed, resulting in 51.7% PR and 33.9% IR. The IRs and PRs in the 6 months after the biopsy showed that pregnancy was not related to the local injury. Twenty-two RIF patients (25.9%) were NR, and in 15 of them a second ERA validated a displacement of the window of implantation (WOI). In eight of them, pET was performed on the day designated by the ERA, resulting in 50.0% PR and 38.5% IR. These results should be considered as preliminary.

Conclusion(s): There is an increased percentage of WOI displacement in RIF patients compared with comparison group patients, leading to the concept of pET as a therapeutic strategy. Rescue of NR patients by pET in a displaced WOI results in similar PR and IR.