Endometrial Receptivity Analysis - a tool to increase an implantation rate in assisted reproduction

A successful embryo implantation is crucial for a positive outcome of in vitro fertilization. But there is only a short period during which the endometrium is receptive for embryo, this so called implantation window can be detected by a molecular diagnostic method endometrial receptivity analysis (ERA).

To find out the percentage of patients with a non-receptive endometrium in the time of ERA and to learn what part of them got pregnant after the identification of their personalized implantation window.

A retrospective study.

REPROMEDA Biology Park, Centre of Reproductive Medicine and Preimplantation Genetic Diagnosis, Brno.

A cohort of 85 patients undergoing ERA from August 2015 to October 2018 was studied. 74 patients experienced a previous implantation failure, the average number of preceding unsuccessful frozen embryo transfers was 2,5 in this group, 11 women went through ERA due to the preventive reason before the first FET. In all women one euploid embryo was transferred. 48 patients were prepared either for ERA or FET in a natural menstrual cycle, 37 women in HRT cycle. We were interested in a percentage of non-receptive patients in the time of ERA and wanted to discover what part of non-receptive women got pregnant after the identification of their personal implantation window. The average number of frozen embryo transfers needed to achieve the pregnancy was also calculated.

31 of 85 patients (36.5%) were found to have a non-receptive endometrium. In the natural cycle 13 of 48 (27.1%) were non-receptive: five were pre-receptive, three early receptive, two late receptive and three post-receptive. In the HRT cycle 18 of 37 patients (48.6%) were non-receptive: 12 were pre-receptive, four early receptive, one late receptive, one post-receptive. Personalized FET was done in 26 of total 31 initially non-receptive patients, 18 of them got pregnant (69.2%). In the natural cycle 6 of 11 (54.5%) achieved the pregnancy, in the HRT cycle 12 of 15 women (80.0%) got pregnant. To achieve the clinical pregnancy 1.5 frozen embryo transfer in average was needed.

A displaced implantation window was found in more than 1/3 of patients undergoing an assisted reproductive treatment. After the personalized FET the clinical pregnancy was noticed in 69.2% of them. This result supports an individual approach to patients in IVF programme besides other at the timing of embryo transfer after the identification of pWOI.