ERA Test in IVF: History, Evidence, and What NICE, ESHRE, ASRM and HFEA Say Now

Key Takeaways

An ERA test reads a gene-expression profile from a biopsy to suggest personalised transfer timing. The idea grew from limits of microscope dating, but randomised evidence does not support routine use to improve live birth. The Doyle trial excluded recurrent implantation failure. In 2026 NICE recommends not offering endometrial receptivity testing — including ERA and microbiome panels such as EMMA/ALICE — as a transfer add-on.

Key evidence: NICE NG257 — Fertility problems (2026), recommendation 1.41.1 · NICE — Evidence review D: endometrial receptivity testing · Doyle et al. — randomised trial, JAMA 2022 (PMID 36472596)

After repeated negative transfers, a question often returns: “What if it is not the embryo, but the timing?” That is what an ERA test (endometrial receptivity analysis) claims to clarify. It analyses gene expression in a sample of the uterine lining to estimate a receptive period, then suggests moving transfer earlier or later. The report does not establish why a previous transfer failed.

Randomised trials have tested whether this change in timing leads to more live births. In 2026, NICE NG257 made a clear recommendation: do not offer endometrial receptivity testing as an embryo-transfer add-on.

What an ERA test is trying to measure

ERA classifies the lining’s gene-expression profile at the time of biopsy. It does not measure the uterus’s overall ability to support a pregnancy.

ERA starts with an endometrial biopsy. The lab compares the expression of many genes with a “receptive” signature. Reports usually label the lining receptive, pre-receptive, or post-receptive. If the report suggests a shift, the team may adjust progesterone exposure before a later frozen embryo transfer. That is personalised embryo transfer. Ultrasound thickness and gene expression are different measures: a thick lining may be labelled non-receptive by ERA, but the label does not establish why a transfer failed.

Other commercial panels promise much the same idea under other names. They offer a possible explanation for a failed transfer. The clinical question is whether acting on that explanation increases live birth.

How the test was developed

ERA grew out of attempts to date the uterine lining more consistently. Later trials examined whether using its results actually improved transfer outcomes.

Before ERA: dating the lining under the microscope

For a long time, clinicians tried to “date” the endometrium on a slide (Noyes criteria and related systems). The goal was already embryo–lining synchrony. In practice, morphological dating varied a lot between readers. It did little to guide modern IVF transfer timing.

2000–2011: from research to the first ERA

Teams looked for a molecular signature of receptivity in gene expression across the cycle. In Díaz-Gimeno and colleagues’ 2011 study, the researchers published a clinical tool based on a large gene panel (about 238 at first) and an algorithm that classifies the result: the endometrial receptivity array. Patenting and commercial development by Igenomix then moved the idea from the research lab to a commercial test.

The starting hypothesis was simple. In some patients with repeated failure, the implantation window might be shifted. Transferring at the “right” time might then help.

After 2011: sequencing, finer timing, ERA + microbiome packs

Later versions used next-generation sequencing, which reads genetic activity. The ASRM 2026 opinion describes a panel of 248 genes. Reports often propose shifting progesterone timing by hours or days in the next cycle. A second biopsy is sometimes asked for to confirm the window.

Later, ERA was offered with microbiome and chronic infectious endometritis panels (EMMA, ALICE) in packs such as EndomeTRIO. These panels look at other aspects of the lining, and NICE 2026 places them under the same do not offer add-on recommendation.

Why the test spread so fast

It offers both an explanation (“your window is shifted”) and a next step (“transfer 12–24 hours earlier or later”). After failure with a good-looking — or euploid — embryo, that story is easy to grasp. The test was widely offered before the larger randomised trials had reported.

What an ERA cycle looks like in practice

The biopsy is usually taken in a preparatory cycle that reproduces the intended frozen-transfer protocol. If the result is used, transfer takes place in a later cycle with timing based on the report.

Typical steps:

1. Prepare a mock or programmed cycle as close as possible to the future transfer protocol (often hormone replacement).
2. Take an endometrial biopsy after a set number of hours of progesterone.
3. Receive a profile (receptive / pre / post) and any recommended shift.
4. Repeat a similar preparation for transfer, with adjusted timing.

That adds cost, delay, and sometimes a second biopsy. The HFEA safety information also describes cramps, a small risk of infection or bleeding, and a very small risk of uterine perforation.

What major clinical trials show

Some early studies reported encouraging results, but no statistically significant live-birth benefit was found in the randomised trial of single euploid blastocyst transfer (Doyle 2022). Euploid means that testing found the expected number of chromosomes.

Doyle’s trial excluded patients with recurrent implantation failure or recurrent pregnancy loss. Its result cannot establish what happens in those groups; it also does not demonstrate that ERA helps them.

A “non-receptive” label alone does not establish the value of an add-on. The key question is whether using the result improves live birth in a population comparable to yours. On that point, current guidance stays cautious.

What NICE, ESHRE, ASRM and HFEA say now

These bodies do not support routine receptivity testing. NICE 2026 explicitly recommends not offering it as a transfer add-on.

Why NICE is so firm

In the NG257 rationale, the committee sees no important difference in clinical pregnancy and live birth between ERA-timed frozen transfer and standard timing. Its recommendation is not to offer these tests as transfer add-ons.

For patients treated outside the UK, NICE is not local law. Its committee reviewed the same trials that clinicians elsewhere rely on, so it is reasonable to ask your centre how it interprets the recommendation.

ERA, EMMA, ALICE: what NICE actually covers

Recommendation 1.41.1 covers gene-expression tests and microbiological tests offered as transfer add-ons.

• ERA (and gene-expression equivalents): timing / implantation window.
• EMMA / ALICE: microbial or infectious endometrial profiles, often sold as a step toward antibiotics or other interventions.

NICE notes a lack of strong evidence for microbiome “test then treat” strategies. It asks for research on those treatments — while still saying do not offer these tests as add-ons today.

The recommendation applies to each test, so it also applies when ERA, EMMA and ALICE are sold together in one commercial pack.

What to review before agreeing to a receptivity biopsy

Embryo factors, the uterine cavity and the transfer protocol deserve review before a receptivity biopsy is considered, as outlined in the ESHRE recommendations.

Before a receptivity test, review:

• embryo quality or ploidy — see IVF embryo grading;
• uterine cavity (polyps, adhesions, septum);
• transfer technique;
• hydrosalpinx;
• chronic endometritis when indicated;
• progesterone route and timing in the actual protocol;
• fresh vs frozen transfer strategy.

These checks address findings that may change management. A test described as “personalised” still needs evidence that acting on its result improves outcomes.

Clinical note — Dr. Aksoy’s approach

ERA is not part of my standard assessment or treatment pathway. When a patient with repeated failed transfers specifically raises it after standard causes have largely been ruled out, I talk through the evidence, the uncertainty and the cost; that conversation is not a recommendation to have the test (see the first question in the FAQ below).

I do not offer ERA routinely, and I do not offer it as a ‘last resort’ after several failed transfers either. Current studies have not shown that timing transfer to an ERA report raises live birth compared with standard progesterone timing — including with euploid embryos. Scientific committees do not support routine use. Presenting an invasive, costly test without proven live-birth benefit as a final option, leaning on a patient’s exhaustion, does not feel ethical to me.

What I say in clinic: failed implantation does not prove that your implantation window is shifted. ERA has not been shown to diagnose that reliably, or to improve live birth when timing is changed on its result. I do not recommend spending money and time on this test.

What bothers me most is hearing, after a few negative transfers, ‘your window may have shifted’ — with ERA presented as the missing piece. Scientific uncertainty should be said out loud. Pushing an unproven test through the fear of ‘leaving no stone unturned’ is not good practice.

After cavity factors, possible hydrosalpinx, transfer technique and the embryo have been reviewed, the more rational path is still: start progesterone on the right day and hour, keep dosing consistent, and check serum progesterone when indicated. If failure continues, we revisit the same standardised protocol. We do not move on to ERA.

Questions worth asking before you decide

If a receptivity test has been proposed, ask how it would change your care and which evidence supports that change.

1. How have you assessed repeated implantation failure in my case? ESHRE suggests considering further investigation when transfers have failed despite a predicted cumulative implantation chance exceeding 60%; this is not a fixed number of transfers.
2. What will change exactly in the next frozen transfer if the report says pre- or post-receptive?
3. Have you already set standard progesterone timing without a biopsy?
4. How do you read Doyle 2022 and NICE 1.41.1 in my case?
5. If transfer still fails after “personalised” timing, what finding would guide the next step?

Frequently Asked Questions for Dr. Aksoy

Does ERA improve live birth, and do you recommend it?

I do not routinely recommend ERA for any patient group: there is not enough evidence that it increases live birth.

If a patient with repeated failed transfers specifically asks about it after standard causes have largely been ruled out, I can discuss the evidence, uncertainty and cost. That discussion is not a recommendation to have the test. ERA is not part of my standard assessment or treatment pathway.

I first review embryo quality, the uterine cavity, possible hydrosalpinx, transfer technique and other more common causes of failure.

How is the biopsy taken, and is it painful?

A thin catheter passes through the cervix to take a small sample of the uterine lining. The procedure usually takes a few minutes. Most patients describe brief period-like pain or cramps; light spotting may follow.

Serious complications are rare. There is no evidence of lasting damage to the uterus, but taking a biopsy simply to “stimulate” the lining has not been shown to improve the chance of pregnancy.

How do you approach ERA, MatriceLab and EMMA/ALICE panels?

I first explain that these are different tests. ERA tries to assess transfer timing; MatriceLab examines some immune-related features of the lining; EMMA/ALICE examine the uterine microbiota and certain bacteria.

An interesting result is different from evidence that treatment guided by that result produces more live births. There is not enough strong evidence for the latter. I therefore do not order these panels automatically after every failed transfer; I first look for better-established causes that could change the outcome.

Sources

• NICE. Fertility problems: assessment and treatment (NG257). 2026. Recommendation 1.41.1.
• NICE. Evidence review D: endometrial receptivity testing. 2026.
• NICE. Rationale and impact — endometrial receptivity testing.
• ESHRE Working Group on Recurrent Implantation Failure. ESHRE good practice recommendations on recurrent implantation failure. Human Reproduction Open. 2023.
• ASRM Practice Committee. Recurrent implantation failure: a committee opinion. 2026.
• Human Fertilisation and Embryology Authority. Endometrial receptivity testing.
• Doyle N et al. Effect of Timing by Endometrial Receptivity Testing vs Standard Timing of Frozen Embryo Transfer on Live Birth in Patients Undergoing In Vitro Fertilization: A Randomized Clinical Trial. JAMA. 2022;328(21):2117-2125. doi:10.1001/jama.2022.20438.
• Zolfaroli I et al. Impact of Endometrial Receptivity Analysis on Pregnancy Outcomes In Patients Undergoing Embryo Transfer: A Systematic Review and Meta-Analysis. J Assist Reprod Genet. 2023;40(5):985-994. doi:10.1007/s10815-023-02791-2.
• Simón C et al. A 5-year multicentre randomized controlled trial comparing personalized, frozen and fresh blastocyst transfer in IVF. Reprod Biomed Online. 2020;41(3):402-415. doi:10.1016/j.rbmo.2020.06.002.
• Díaz-Gimeno P et al. A genomic diagnostic tool for human endometrial receptivity based on the transcriptomic signature. Fertil Steril. 2011;95(1):50-60, 60.e1-15. doi:10.1016/j.fertnstert.2010.04.063.

Dr. Senai Aksoy

Dr. Senai Aksoy studied and trained in France before returning to Turkey, where he was a member of the ICSI team at Sevgi Hospital, Ankara — the country's first ICSI centre (1994-95) — and a co-author on the first Turkish ICSI publications produced in collaboration with the Brussels Van Steirteghem group (Human Reproduction, 1996; PMID 8671323). He helped build the IVF programme at the American Hospital Istanbul and has been running his own fertility practice since 1998.

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The content has been created by Dr. Senai Aksoy and medically approved.