ERA - Genetic Test for Womb Receptivity|NU Fertility

ERA (Endometrial Receptivity Array) Test

The ERA Endometrial Receptivity Analysis is a personalized genetic test to diagnose the state of endometrial receptivity in the window of implantation.

An endometrium is receptive when it is ready for the embryo implantation. This occurs around days 19-21 in each menstrual cycle of a fertile woman. This period of receptivity is what we call the window of implantation.

The lack of synchronisation between the embryo ready to be implanted and endometrial receptivity is one of the causes of recurring implantation failure. This is why it is imperative to assess the endometrium in order to determine the optimal day for embryo transfer.

The ERA test requires an endometrial biopsy that should be carried out on day LH+7 (natural cycle) or day P+5 (HRT cycle). This biopsy is quickly and easily taken by a gynaecologist in their consultation room. After being sent away, the sequencing expression of 236 genes involved in the endometrial receptivity is analysed. An in-house designed computational predictor analyses the data obtained, classifying the endometrium as Receptive or Non-Receptive.

This test has been performed on patients who have had recurring implantation failure with embryos of good morphological quality. This test is recommended for patients with seemingly normal uterus and normal endometrial thickness (≥6 mm), in which no problems are detected. A displaced window of implantation is detected in approximately 25% of these patients. This analysis helps determine the personalised window of implantation, enabling personalized embryo transfer (PET) to be performed on the basis of these results.