What is endometrial receptivity array?

Endometrial receptivity array (ERA) is a test that claims to find the optimal time for an embryo to be transferred into a woman’s uterus for the embryo to implant, known as the window of implantation. ERA involves taking a biopsy of  the endometrial lining of the uterus and testing the tissue to see which genes are expressed.

When combined with a computational predictor these results indicate when the endometrium may be most receptive to an embryo implanting. The endometrium will be categorised as either receptive, pre-receptive, or post-receptive. In subsequent cycles of treatment, the patient will then have what is termed a ‘personalised embryo transfer’, taking place at the optimal time for her specific window of implantation. This would theoretically increase the chances of the embryo implanting successfully and the patient having a baby. However, there is a question over whether a patient has the same window of implantation for each of their cycles of treatment.

Risks of endometrial receptivity array

As this procedure requires obtaining a biopsy of the endometrium patients can experience cramping and there is a small risk of infection and bleeding. There is also a very small chance of uterine perforation. The biopsy may need to be repeated in the rare event that either the results are inconclusive, or the biopsy fails to obtain a sufficient quantity or quality of tissue for testing.

ERA requires patients to undergo a freeze-all cycle which carries a small risk that any frozen embryos would not survive the thawing process. ERA does not carry any additional known risks for the child born as a result of fertility treatment.

Research

One RCT has been performed to study the effectiveness of ERA at increasing a patient’s chances of having a baby. The outcomes of the study were promising but the results did not prove that ERA made a true difference to the patient’s chances of having a baby and we can’t be certain of their reliability.

Current HFEA grading

For more information, please visit the HFEA website