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.