Endometrial Receptivity Array (ERA)

Most of the couples undergoing IVF treatment, conceive in upto three cycles. However there is a small proportion of couples who fail to conceive even after 3 cycles of IVF and are said to be suffering from recurrent implantation failure. Advanced testing is recommended in such patients and endometrial receptivity array (ERA) is one of the tests that can be done in such cases. It is a molecular diagnostic test that tests 238 different genes to find out the “window of implantation” or the best time for embryo transfer in a particular patient.

How does ERA help?

Consider embryos are the seeds and endometrium is the soil. For the seed to grow into a healthy plant, soil should have all the necessary minerals and nutrients in the right amount to nurture the plant. If it is not the case, then no matter how good quality the seed is, it’s never going to grow if it is implanted into an unprepared or hostile soil.

Success in IVF is a close interplay of good embryos and a receptive endometrium. Most of the embryos are now a days grown till blastocyst stage and then transferred. Meanwhile the patient who is receiving the embryos also receives progesterone hormone via vaginal gel or capsule or injections to prepare the endometrium to receive blastocyst embryos. It is assumed that after 6 days of this progesterone therapy endometrium becomes ready for implantation of blastocyst. But in few patients, the endometrium either matures early (say after 5 days of progesterone) or in some cases it matures late (say after 7 days of progesterone). These patients are said to have displaced “window of implantation” and require specially timed embryo transfer (personalised embryo transfer).

Who should opt for ERA?

Patients with 3 or more IVF failures
Can also be considered earlier in
A) Patients with thin endometrium
B) 2 cycles failed with donor eggs

How is ERA done?

For ERA, your endometrium is prepared in the similar manner as it is prepared during embryo transfer cycle. On the day when embryo transfer is supposed to be done, instead of embryo transfer a biopsy of inner lining of uterus(endometrium) is taken and sent for analysis. This procedure does not require anaesthesia and thus can be done on out patient basis. It is not a painful procedure but can cause a little discomfort which can be managed by simple analgesics.

How is ERA report interpreted?

A normal ERA report labelled as receptive endometrium is reassuring and in such patients other possible causes of IVF failure should be looked for.
Abnormal ERA report can be labelled as either Pre-Receptive Endometrium or Post-receptive endometrium.

In patients whose report is abnormal means that their endometrium is not ready to receive and implant the embryos after conventional progesterone therapy and in them a personalised embryo transfer should be done 1/2 day prior or later than usual depending on ERA report recommendation.

Why one should avail it?

In today’s era of advanced medicine, “one size fits all” policy is not acceptable. Repeated IVF failures can be emotionally, physically and financially draining for the couples. Some studies have shown that in women who have 3 or more IVF failures, displaced window of implantation is seen in upto 27.5% of patients and these patients can be benefitted from ERA.
ERA is simple , reproducible and does not change over long duration like 1-2 years and thus does not need to be repeated.

How much does ERA cost?

ERA costs around 35-40,000 INR which is much less than a single IVF cycle.