The endometrial receptivity test provides information on the ideal moment to transfer the embryos into the woman's uterus.
Within the study of a patient who has had implantation failures or repeated miscarriages, the ERA is indicated to analyze the optimal window for embryo transfer (in addition to other factors such as the study of pathogens at the endometrial level, the analysis of the microbiota and a hematological and immunological evaluation). Depending on the results of the endometrial receptivity test, we will know exactly how many hours of progesterone (and at what dose) are necessary for the embryo transfer.
There is a possibility that the window of implantation may be altered, even if there has been a normal evolutionary gestation previously. The embryo implantation in a spontaneous pregnancy, surely, has not occurred at the same moment in which we would make the transfer in an assisted reproduction treatment. Not only this, but various factors (such as a significant change in the patient's weight, for example) can modify the implantation window already studied in a woman, so it is sometimes advisable to repeat the endometrial receptivity test if a long time has passed since the first test or if there has been a significant weight loss or gain in the patient.
How do we carry out this study? We indicate the same endometrial preparation that we would perform at the time of the embryo transfer, but on the day of the supposed transfer is when we perform this sample collection. It is a very simple procedure: with the speculum we visualize the cervix and with a small cannula that we introduce through it we take the endometrial material that we send for analysis. It is not usually an uncomfortable procedure and sedation of the patient is not necessary.
Often with a single sample we can take advantage of the procedure to study the existence of pathogens and the endometrial microbiota, in addition to the window of implantation.
