ERA & endometrial receptivity testing: is it worth it?

When an embryo transfer fails, especially repeatedly, it is natural to look for an explanation. One of the tests proposed in these cases is the ERA (Endometrial Receptivity Analysis) — a test that promises to find the “ideal window” of implantation.

The idea is attractive. The question, however, is whether this test actually leads to more babies — or whether it adds cost and delay without proven benefit.

What is the ERA and what does it promise?

The ERA is a test that analyses the expression of dozens of genes in a small endometrial sample, taken by biopsy on a set day of a mock cycle. The aim is to determine whether the endometrium is “receptive” at that particular moment.

The hypothesis is that, in some women, the “window of implantation” is displaced, and that by adjusting the day of embryo transfer (personalized transfer) success might be increased.

What do the randomized trials show?

Here lies the crucial point. Well-designed randomized trials have not shown that ERA-guided personalized transfer increases the live-birth rate compared with standard transfer.

In other words, although the theory is reasonable, the practical application of ERA has not delivered the expected benefit on the hard outcomes — that is, the birth of a healthy child.

What do the guidelines say?

Similarly, the UK regulator HFEA places endometrial receptivity testing in the category of add-ons without sufficient evidence of effectiveness for the general population.

Is there any case where it might be considered?

In very selected cases — for example women with repeated failure to implant good-quality embryos despite smooth preparation — some clinicians may discuss ERA as an experimental option, always with clear information about the lack of proven benefit.

Even then, it should not be presented as a test that “will solve the problem”. It is a tool under question, not an evidence-based solution.

What is the cost and the risk?

The ERA carries a significant financial cost and requires an extra, mock cycle with an endometrial biopsy. This means delaying the actual embryo transfer — time that, especially in older women, is not negligible.

The physical risk of the biopsy is small, but the real cost is the combination of expense, delay and expectation that may not be justified by the data.

How should you discuss it with your doctor?

If ERA is proposed, ask directly: is there a randomized trial showing it increases the birth rate in my case? What is the cost and the delay? Is there a simpler alternative?

A doctor practising evidence-based medicine will explain honestly that, for the general case, ERA has not proven its benefit. A well-executed embryo transfer, with proper endometrial preparation, remains the foundation.

Summary

The ERA promises to identify a personalized “window of implantation”, but randomized trials have not shown that ERA-guided personalized transfer increases the live-birth rate. Both ESHRE (2023) and HFEA do not recommend it as routine. It adds cost, a biopsy and the delay of an extra cycle. For the general case it is not worth it; a well-executed transfer with proper endometrial preparation remains the essence.

Sources: ESHRE, “Good practice recommendations on add-ons in reproductive medicine”, Hum Reprod 2023; HFEA add-ons list with traffic-light rating system; Fertility and Sterility, systematic review and meta-analysis of the ERA before frozen embryo transfer cycles.

⚕ Medically reviewed by Prof. Stratis Kolibianakis · Thessaloniki Medical Association Reg. No. 16340

ARTICLE 19 · INFERTILITY & DIAGNOSIS