You have done the injections, the monitoring scans, the retrieval, and the transfer. The embryos were good (your embryologist said so). And then, again, nothing. A flat beta. A negative test. And the question that keeps circling: why is the embryo not implanting?
For most women, a single failed transfer is part of IVF. For some, it happens again. And again. This pattern, three or more failed transfers despite good-quality embryos, is what clinicians call recurrent implantation failure (RIF). It is not a diagnosis in the way that PCOS or endometriosis is a diagnosis. It is a pattern that says: something in the interaction between embryo and endometrium is not working, and we need to look more carefully.
This post explains what we look for and why, what the ERA test is and what the evidence shows about it, and how to have a useful conversation with your IVF team about what to do next.
What “Recurrent Implantation Failure” Means
There is no universal consensus on the precise definition of RIF, which is worth knowing because it affects how different clinics approach it. A widely cited definition from Coughlan C et al. (Hum Reprod, 2014) described RIF as the failure to achieve a clinical pregnancy after transfer of at least three good-quality embryos across one or more IVF cycles in a woman under 40.
In practice, most units begin the RIF investigation after two or three failed blastocyst transfers, particularly if the embryos were graded well on day 5. Blastocysts rather than day-3 cleavage-stage embryos are the reference point here, because blastocysts that look good on day 5 have already crossed the first developmental hurdle, and so their continued failure is more informative.
The term “failed implantation” can also apply to biochemical pregnancies, where the hCG rises briefly and then falls. If this pattern keeps repeating, most clinicians treat it similarly to a negative transfer in terms of what warrants investigation.
What Causes Recurrent Implantation Failure?
Causes fall into three broad areas: the embryo itself, the uterine environment, and the timing of the transfer relative to the endometrium’s receptive window. There is also a smaller category of immune and clotting factors. In many cases, more than one factor contributes.
Embryo Quality: The Most Common Cause
Even embryos that look perfect under a microscope can carry chromosomal abnormalities that prevent implantation or cause very early loss. This is the most common single reason IVF cycles fail. In women over 37, the proportion of aneuploid embryos (those with the wrong number of chromosomes) rises substantially, which is why older women often need more cycles.
Preimplantation Genetic Testing for Aneuploidies (PGT-A), done on day 5 biopsied embryos before freezing, identifies which embryos are chromosomally normal. If you have been transferring untested embryos, moving to PGT-A for the next batch is often the first recommendation. It does not eliminate all risk of failure, but it removes the most common variable from the equation.
For information on the broader IVF process and what success rates look like by age, IVF success rates in India by age has the numbers in context.
Uterine Factors
The uterine cavity needs to be clear and the endometrial lining needs to be at the right thickness and pattern for implantation to occur. Common structural issues include:
Endometrial polyps. Small benign growths inside the cavity. They are easy to miss on a routine ultrasound and often require a saline sonography or hysteroscopy to detect properly. Removal before the next transfer is standard practice.
Submucosal fibroids. Fibroids that push into the cavity can mechanically interfere with implantation. Not all fibroids need treatment before IVF, but submucosal ones usually do. For more on fibroids and implantation, see can I conceive naturally with fibroids.
Intrauterine adhesions (Asherman’s syndrome). Scarring inside the uterine cavity, often from a previous D&C or infection, can reduce receptivity. This is diagnosed and treated by hysteroscopy. The Asherman’s syndrome guide covers this in detail.
Thin endometrium. A lining below 7 mm on transfer day is associated with lower implantation rates. The cause is usually poor blood flow, sometimes related to previous uterine surgery or infections. The endometrial thickness guide explains what the numbers mean and what can be done.
A hysteroscopy is the most direct way to inspect the cavity and address polyps or adhesions at the same time. Many RIF protocols include a diagnostic hysteroscopy before the next transfer.
The Implantation Window and Endometrial Receptivity
This is where the ERA test enters the picture, so it is worth understanding the biology first.
The endometrium is not receptive all the time. There is a specific window, usually a 3-to-5-day period in the mid-luteal phase of each cycle, when the surface of the lining is primed for an embryo to attach. Outside this window, even a chromosomally normal embryo will not implant. In a standard frozen embryo transfer protocol, the progesterone start date is calibrated to hit this window on the day of transfer.
For most women, this timing works as expected. For some, the window falls slightly earlier or later than average. If that shift is consistent cycle to cycle, every transfer lands outside the window, and the embryo, even if normal, does not attach.
This is what the ERA test attempts to detect.
The ERA Test: What It Is and How It Works
ERA stands for Endometrial Receptivity Analysis (sometimes also called Endometrial Receptivity Array). It is a test developed and commercialised by Igenomix, which operates laboratories in India and internationally.
The test involves a small endometrial biopsy taken during a mock cycle. A mock cycle is identical to a real frozen embryo transfer cycle in terms of medication protocol, monitoring scans, and timing, but without an embryo transfer. The biopsy is taken on the day that would normally be transfer day.
The tissue sample is analysed for the expression of 248 genes known to be involved in endometrial receptivity. Based on this gene expression pattern, the result falls into one of three categories: receptive, pre-receptive, or post-receptive.
If the result is pre-receptive, the endometrium is not yet ready at the standard timing, and the lab recommends extending progesterone by 12 to 24 hours before the next transfer. If post-receptive, the timing needs to come forward. If receptive, no change is needed.
A transfer guided by ERA results is called a Personalised Embryo Transfer (pET).
ERA test cost in India: The test typically costs between Rs. 30,000 and Rs. 50,000 depending on the clinic and whether Igenomix processes the sample directly or through a partnered laboratory. This is in addition to the cost of the mock cycle and any other investigations.
What the Evidence Shows About ERA
I am Dr. Suganya Venkat, an OB-GYN with over fifteen years of clinical experience, and this is the part I want to be direct about: the ERA test has generated significant enthusiasm, but the evidence supporting routine use is not as strong as it might appear from the way it is sometimes marketed.
The early data on ERA was promising. Observational studies suggested that about 25 to 30 percent of women with RIF have a displaced window of implantation, and that correcting the timing improved their outcomes. That finding made intuitive sense and drove widespread adoption.
Then came the STAR trial (Simon C et al., 2020), the first properly powered randomised controlled trial designed to test whether ERA-guided pET actually improves outcomes compared to standard transfer timing in women with RIF. It did not find a statistically significant improvement in ongoing pregnancy rate.
What does this mean in practice?
It means that ERA is not a guaranteed solution, and using it as a first investigation in every woman with failed transfers is not well-supported by current evidence. However, it also does not mean the test has no value. A subset of women, likely those with a genuinely displaced window, may benefit from the timing correction. The difficulty is that we cannot reliably identify those women without doing the test.
The current clinical position from bodies like the ESHRE (European Society of Human Reproduction and Embryology) is that ERA may be considered in selected cases of RIF, after other causes have been addressed, rather than as a first-line universal investigation. Your IVF team’s recommendation will depend on your specific history and what has already been investigated.
Other Investigations Worth Knowing About
ERA is not the only add-on offered to women with RIF. Here are others your clinic may discuss:
EMMA and ALICE. Also from Igenomix, these tests assess the endometrial microbiome. EMMA detects the balance of bacteria in the uterine environment; ALICE tests for specific pathogenic bacteria such as Enterococcus and Streptococcus that can impair implantation. Both are done from the same biopsy sample as ERA, usually bundled. Evidence for routine use is limited, but for women with recurring unexplained failure, they are worth considering alongside ERA.
Sperm DNA fragmentation testing. High sperm DNA fragmentation impairs embryo development and can cause implantation failure even when morphology and count look normal. If DFI has not been tested, it is a reasonable addition to the workup. The sperm DNA fragmentation guide covers what the test measures and what high levels mean for the next cycle.
Thrombophilia screening. Inherited clotting disorders, including factor V Leiden, prothrombin gene mutation, and protein S or C deficiency, can impair blood flow to the implantation site. Acquired thrombophilia, particularly antiphospholipid syndrome, is also a well-recognised cause of both RIF and recurrent miscarriage. A thrombophilia screen includes blood tests for these conditions, and if positive, treatment with low molecular weight heparin or aspirin during the transfer cycle may be recommended. The tests for recurrent loss overlap significantly here: recurrent miscarriage investigation guide is worth reading if you have had both failed transfers and early losses.
Uterine NK cell testing. Elevated natural killer cells in the endometrium have been proposed as a cause of RIF. This is an active area of research, but treatment approaches (including intravenous immunoglobulin and intralipid infusions) remain experimental and are not currently supported by robust RCT evidence. Approaches vary significantly between clinics.
PGT-A. If not already done, genetic testing of embryos is the most evidence-backed addition to a failed-transfer workup. Even one or two normal-tested embryos transferred subsequently often perform better than multiple untested ones. Frozen embryo transfer: steps and protocol explains how the process works when you move to a freeze-all and test approach.
If you would like to talk through your specific history and which investigations make sense for your situation, you can start a conversation with Dr. Suganya Venkat over a video consultation at Fertilia.
A Practical Investigation Sequence
Not every test needs to be done at once, and the order matters. Here is a logical sequence to discuss with your team:
Step 1: Rule out uterine cavity issues. Before any further transfers, a hysteroscopy or saline infusion sonography to inspect the cavity. If a polyp or adhesion is found and treated, this alone can change outcomes.
Step 2: Review embryo quality. If you have been transferring untested embryos and have remaining eggs, consider adding PGT-A to the next batch before another transfer. If all embryos are used, discuss the plan for a fresh cycle with testing.
Step 3: Sperm DNA fragmentation. If not already done, test before the next retrieval cycle. Oxidative stress reduction, antioxidant supplementation, and in some cases TESA or PESA for testicular sperm can improve DFI.
Step 4: Thrombophilia screen. A blood test done at any point. If positive, heparin or aspirin during the next cycle can be added without significant risk.
Step 5: Consider ERA. If steps 1 to 4 have been addressed and transfers are still failing, ERA as part of a mock cycle becomes a reasonable next step. It is not a guaranteed answer, but for a genuine minority it identifies a correctable timing issue.
Step 6: Immunological investigations. NK cell testing and related investigations fall here, under specialist guidance, with clear expectations that evidence for treatment is still evolving.
Throughout all of this, your own IVF clinic’s view matters because they know your full history. The goal of this post is to help you walk into those conversations understanding the framework, not to suggest you navigate RIF without specialist guidance.
What to Think About Diet and Lifestyle During This Period
The body of evidence on lifestyle and RIF is smaller than for other fertility conditions, but some things are consistent with general IVF optimisation:
An anti-inflammatory eating pattern, grounded in dal, dahi, ghee, vegetables, and small amounts of fish or eggs if you eat them, supports the endocrine environment more broadly. CoQ10 (ubiquinol form, 200 to 600 mg daily) is commonly used in the IVF period for egg quality and has a reasonable evidence base for mitochondrial support.
Consistent sleep, keeping alcohol out of the cycle months, and managing cortisol are all worth attending to, not because they are guaranteed to change an outcome, but because a body that is not fighting stress concentrates its resources better.
These are supportive, not corrective. If a displaced implantation window or a submucosal fibroid is the underlying cause, lifestyle alone will not resolve it.
Frequently Asked Questions
What is the definition of recurrent implantation failure?
Most clinicians define RIF as three or more failed embryo transfers despite good-quality embryos, in a woman who has had her uterine cavity assessed and cleared. Some units use two failed blastocyst transfers as the threshold to begin investigation, particularly in women over 37 where time matters. The definition is not universally agreed upon, which is why different clinics may propose the ERA or other investigations at different points.
The ERA test ke baad kya hota hai? (What happens after the ERA test?)
After the biopsy, the sample goes to the lab for gene expression analysis, which takes around two to three weeks. If the result is pre-receptive or post-receptive, the lab issues a personalised transfer recommendation adjusting the progesterone duration by 12 to 24 hours. Your clinic then plans the next transfer using this adjusted timing. If the result is receptive, no timing change is needed and other causes become the focus.
Is the ERA test worth doing after one failed transfer?
Generally not. One failed transfer, even with a good embryo, falls within the expected statistical range for IVF. ERA and the full RIF workup become relevant after two to three failed blastocyst transfers. Beginning investigations earlier, without a pattern, tends to produce more uncertainty than clarity.
Does ERA guarantee a successful transfer?
No. The test identifies whether your implantation window is at standard timing or shifted, but it does not address chromosomal embryo quality, uterine structural issues, or immune factors. Women with a genuinely displaced window who receive a correctly timed transfer do have improved outcomes in observational data, but the randomised trial evidence has not confirmed a benefit for all RIF patients. ERA is one piece of a broader investigation, not a standalone fix.
How much does the ERA test cost in India?
The test itself typically costs Rs. 30,000 to Rs. 50,000, depending on the laboratory and whether it is done as a standalone ERA or bundled with EMMA and ALICE. This does not include the cost of the mock cycle (monitoring scans and medication), which is billed separately by the clinic. Igenomix processes ERA samples in India through partner clinics, so availability is reasonably good in metro cities.
Should I consider PGT-A before doing ERA?
For most women with RIF who have been transferring untested embryos, PGT-A is worth prioritising because chromosomal abnormality in the embryo is more common than a displaced implantation window. A normal-tested embryo that still fails to implant is a stronger indication for ERA than a series of failed untested embryos.
Can recurrent implantation failure be treated without IVF?
RIF by definition occurs in the context of IVF, because that is when transfer outcomes can be specifically tracked. If you are experiencing repeated early losses rather than failed IVF transfers, the investigation overlaps but the clinical framing is different. See the recurrent miscarriage investigation guide and do you need IVF for context on where IVF fits in the broader picture.
Three or more failed transfers is one of the more demoralising points in an IVF journey. What it usually does not mean is that implantation can never happen. In most cases, there is something specific that has not yet been found, and a systematic investigation can find it.
If you would like to talk through your history and which investigations make sense as a next step, you are welcome to reach Dr. Suganya Venkat over a video consultation at Fertilia. She works with women across India, online.
For the complete guide to fertility testing and getting pregnant after diagnosis, download the free Getting Pregnant guide.
