personalized Embryo Transfer (pET) by


(Endometrial Receptivity Analysis)

The Endometrial Receptivity Analysis (ERA®) is a molecular tool that analyzes by NGS the transcriptome of 236 genes related to endometrial receptivity status.

The ERA® can be performed in natural or HRT cycles, according with the kind of cycle in which subsequently the embryo transfer is going to be performed. But not in controlled ovarian stimulation cycles. For that, an endometrial biopsy must be taken reproducing exactly the same conditions that will have the embryo transfer cycle (type of cycle, medication, way of administration…). This is very important in order to make the result reproducible.


ERA is a diagnostic method developed and patented by IGENOMIX R&D department since 2009, after more than 10 years of research. This technique allows us to evaluate the endometrial receptivity status of a woman. 

This biopsy is quickly and easily taken by gynaecologists in their consultation room.


In our laboratory, the sequencing expression of 236 genes involved in the endometrial receptivity is analyzed. An in-house designed computational predictor analyzes the data obtained, classifying the endometrium as Receptive or Non-Receptive.

WHO need


The ERA test has been proven to help patients who have experienced implantation failure while using good quality embryos.

 Implantation, when the embryo attaches to the uterine wall, must take place for a pregnancy to succeed. If a woman does not become pregnant after three consecutive IVF cycles where one or two high quality embryos were transferred per cycle, we diagnose her with “recurrent implantation failure.”

Women diagnosed with recurrent implantation failure will typically undergo an evaluation that includes an anatomic assessment, testing for blood clotting and genetic testing, as these factors have been associated with implantation failure.



The ERA test is used to evaluate the stage of an endometrium to determine if a receptive or non-receptive genetic profile is present at the time of biopsy. In the case where the endometrium is non-receptive, the test enables us to find a personalized window of implantation for each patient.

The purpose of the ERA® test is to locate the optimum day of receptivity, even when there is a displaced WOI, in order to perform a personalized embryo transfer (pET).

For further details about the tool design, published papers provides the scientific evidence that supports this service.



  • The blastocyst transfer should be performed in the same type of cycle and on the same day in which a receptive result was obtained. A receptive result indicates the ideal day on which the blastocyst transfer should be performed. A day 3 embryo should therefore be transferred 2 days earlier.

  • An endometrial biopsy taken from the uterine fundus must be immediately introduced into an ERA cryotube and preserved in a refrigerator (4-8°C/ 39-46°F) for at least 4 hours.

  • In order to ensure the highest sample quality, we recommend shipment to our laboratory take less than 120 hours at room temperature. In addition, the sample should never reach more than 35°C/ 95°F.