The Endometrial Receptivity Array Test (ERA)  is a method of assessing when the endometrium is most receptive, in order to give a personalised embryo transfer.

The receptivity of the endometrium is a crucial factor in determining the success of IVF treatment.

The endometrium is the tissue lining the uterus, which gets thicker during the cycle until it reaches the optimum thickness for implantation following ovulation. The endometrial receptivity is the status in which the endometrium is ready for embryo implantation to take place and it is also called window of implantation. This occurs normally around days 19-21 in each menstrual cycle of a fertile woman.

In some couples who have recurrent implantation failure, it may be that the window of implantation is displaced either back or forward a few days. The ERA test involves taking a biopsy of the womb-lining and analysing the genes of this tissue taken on the day of “normal” receptivity”. The biopsy procedure is simple, fast and performed in clinic in a similar procedure to an embryo transfer.

ERA can identify certain genes that are normally active when the endometrium is receptive, and it can pinpoint these genes and check whether they are switched on or not. This gives a good idea of whether the endometrium is ‘pre-receptive’, ‘receptive’ or ‘post-receptive’. The test will be carried out in the month prior to the treatment cycle, and the results will determine the exact timing of the embryo transfer in the month of treatment.

In up to 20% of couples with repeated implantation failure this result confirms the endometrium is “non-receptive” so the window of implantation is displaced. This can allow us to personalise the day of embryo transfer and optimise the outcome and minimise further failed cycles.