Recurrent Implantation Failure: What It Means and What the Evidence Supports

nd What It Means for Fertility

What Is Recurrent Implantation Failure?

Recurrent implantation failure (RIF) is not a disease with a laboratory diagnosis. It is a clinical scenario, and it exists only in the context of IVF, because implantation cannot be observed in natural conception.

The European Society of Human Reproduction and Embryology describes it as the scenario in which the transfer of embryos considered to be viable has failed to result in a positive pregnancy test sufficiently often in a specific patient to warrant consideration of further investigations or interventions [ESHRE, 2023].

Two things in that description matter enormously and are usually skipped.

“Sufficiently often in a specific patient.” RIF is defined individually, not by a universal number. The older convention — three failed transfers of good-quality embryos — treats a 30-year-old transferring tested blastocysts and a 41-year-old transferring untested day-3 embryos as the same clinical problem. They are not.

“To warrant consideration of further investigations.” RIF is a trigger to investigate, not a diagnosis in itself. It says something unusual may be happening. It does not say what.

In plain terms: RIF is the point at which your run of failures becomes statistically odd enough that it is worth looking for a reason, rather than simply trying again.

How Is RIF Actually Defined Now? The 60% Threshold

The current approach asks a different question from “how many transfers have failed?” It asks: given this patient’s age, embryo type and number of transfers, what was the cumulative chance she should already have conceived?

If that cumulative predicted chance of implantation has passed 60% and no positive pregnancy test has occurred, the couple should be counselled on further investigation. If it has not yet reached 60%, the appropriate advice is usually to proceed with another transfer [ESHRE, 2023].

The practical consequence:

This is why two couples with the same number of failed transfers can receive entirely different and equally correct advice.

The size of the problem this fixed a is worth noting. A systematic review of RIF definitions used in published research found that in most cases the definitions applied did not meet the ESHRE diagnostic threshold, which means much of the literature on “RIF treatments” was not studying RIF patients at all [Human Reproduction Open, 2025]. That is the single most important reason to be cautious about any RIF treatment presented as proven.

“The first question I ask a couple who arrive after three failed transfers is not what tests they have had. It is what was actually transferred, at what age, and what their realistic chance was each time. In a good number of cases the arithmetic shows they have simply not yet had enough opportunity, and the honest answer is that nothing is wrong — they need another transfer, not a panel of investigations. Telling someone that is harder than ordering the panel, but it is the correct thing to do.”

– Dr. Pranay Shah, MS (ObGy), Director & Chief Fertility Consultant

How Is RIF Different From Recurrent Miscarriage?

These are two distinct clinical problems and they are routinely confused, including in clinical settings.

A biochemical pregnancy — a positive test that does not progress — sits between the two: implantation began. That distinction changes the investigation pathway, so it should be recorded accurately in your notes rather than described loosely as “another failed cycle”.

The investigation and treatment of pregnancy loss is a separate pathway, covered on the recurrent miscarriage page. Both conditions are assessed as part of the wider female infertility evaluation.

What Causes Implantation to Fail Repeatedly?

Implantation requires a competent embryo, a receptive endometrium, and correct timing between the two. Repeated failure can arise from any of the three, and frequently no single cause is identified.

Embryo factors

• Chromosomal aneuploidy — the dominant cause, and strongly age-related. Aneuploid blastocysts have negligible implantation potential.
• Embryo quality and developmental competence
• Laboratory and culture conditions

Endometrial and uterine factors

• Submucous fibroids, endometrial polyps, intrauterine adhesions, uterine septum
• Adenomyosis
• Chronic endometritis — persistent low-grade inflammation of the endometrium, usually without symptoms
• Persistently thin endometrium
• Hydrosalpinx

Timing and hormonal factors

• Displacement of the window of implantation
• Inadequate progesterone exposure — including poor absorption of vaginal progesterone, which varies considerably between women
• Premature progesterone rise before a fresh transfer

Systemic and other factors

• Parental chromosomal abnormality — uncommon, with a reported prevalence of around 2% in RIF patients
• Antiphospholipid syndrome, particularly where there is a personal or family history of thrombosis or pregnancy loss
• Thyroid dysfunction
• Lifestyle factors including smoking, tobacco, alcohol and BMI, which can change during the course of treatment

Unexplained In a significant proportion of couples, a full appropriate investigation identifies nothing. That is a legitimate result and does not mean the investigation was inadequate.

Which Investigations Are Actually Indicated?

This is where RIF care most often goes wrong. The 2023 ESHRE recommendations grade nineteen investigations into three categories: recommended, can be considered, and not recommended for routine use.

Recommended

Can be considered

Karyotyping of both partners; 3D transvaginal ultrasound if not already done; hysteroscopy where transvaginal ultrasound raises suspicion of a uterine anomaly; assessment for chronic endometritis, with antibiotics if it is diagnosed; thyroid function; late-follicular and mid-luteal progesterone levels; assessment of specific aspects of endometrial function; imaging for hydrosalpinx where there is doubt [ESHRE, 2023].

On hysteroscopy specifically, the evidence is genuinely split: a meta-analysis in RIF patients reported higher live birth after hysteroscopy, but the largest randomised trial within it — the TROPHY trial, in women with two to four failed cycles and no recognised pathology — found identical live birth rates with and without it (29% versus 29%). Hysteroscopy is therefore appropriate when there is something to look at, and not as a routine ritual after a failed cycle.

Not recommended for routine use

These are the tests most often sold as a “RIF panel”. The ESHRE working group did not recommend them:

Two of these deserve a note, because they are widely offered.

NK cell testing. There is no agreed method of measuring uterine NK cells, no agreed reference range, and no established link between a number on a report and a treatment that improves live birth. A test without a validated normal range cannot generate a valid abnormal result.

Sperm DNA fragmentation. This test has a legitimate role in other clinical contexts, and it is discussed on our own sperm DNA fragmentation page. In the specific setting of RIF, ESHRE does not recommend it, because the data in RIF populations are scarce and a large cohort study found no significant difference in live birth between men above and below the 15% threshold. Reviewing male factors as part of the wider male infertility evaluation is still appropriate — running a fragmentation index specifically to explain repeated implantation failure is not.

What Treatments Are Supported by Evidence?

The pressure to act after repeated failure is intense, and it comes from both directions — the couple wants something done, and the clinic wants to offer something. ESHRE assessed thirteen interventions.

Reasonable to consider

Not recommended for routine use

The ESHRE working group did not recommend the following in RIF: intentional endometrial injury (endometrial scratching); immunomodulation including granulocyte colony-stimulating factor, intravenous intralipid infusion and intravenous immunoglobulin; intrauterine peripheral blood mononuclear cell infusion; intrauterine platelet-rich plasma infusion; intrauterine hCG injection; low molecular weight heparin; GnRH agonist and aromatase inhibitor pre-treatment; and assisted hatching [ESHRE, 2023].

The same position is reflected in ESHRE’s separate good practice recommendations on IVF add-ons, which assessed these interventions across the wider treated population [ESHRE add-ons, 2023]. An umbrella review of interventions for RIF reached a consistent conclusion: where individual meta-analyses report improvements, they are usually in clinical pregnancy rather than live birth, and the underlying evidence is frequently of low certainty [International Journal of Gynecology & Obstetrics, 2025].

On endometrial scratching specifically: meta-analysis of randomised trials in RIF found no significant increase in either pregnancy or live birth, and a subsequent randomised trial comparing hysteroscopy with intentional injury against hysteroscopy alone found no difference in clinical pregnancy.

On immunotherapies specifically: intralipids, IVIG, G-CSF and steroids are not benign. They carry real side-effect profiles, they are expensive, and in RIF they are being given for test results that ESHRE does not recommend generating in the first place. Offering the treatment and the test together is a closed loop with no evidence at either end.

In plain terms: if you have been offered a package of immune tests followed by immune treatments after failed transfers, you are entitled to ask which guideline supports it. There is currently no good answer to that question.

“It is much easier to add something to the next cycle than to explain why we are not adding anything. Couples read the absence of a new intervention as the absence of care, and I understand why. But every one of these add-ons has a cost, some have side effects, and none of them has shown a convincing effect on live birth in this group. My responsibility is to spend a couple’s money and their emotional reserve on the things that can actually change the outcome — the embryo, the cavity, the timing — and to be honest that the rest is being sold on hope rather than data.”

– Dr. Pranay Shah, MS (ObGy), Director & Chief Fertility Consultant

How Is RIF Assessed at Wellspring IVF?

Wellspring IVF & Women’s Hospital is an ART-registered centre (Reg. GS/AHD/024) in Satellite, Ahmedabad, led by Dr. Pranay Shah, MS (ObGy), with more than 15 years in fertility practice and over 6,000 successful IVF outcomes. Consultation, andrology laboratory, embryology unit and operating theatre are in a single facility, which matters in RIF because the transfer, the laboratory and the cavity assessment are all part of the same question.

The approach to a couple presenting after repeated failed transfers:

1. Establish whether this is actually RIF. Age, embryo stage, whether embryos were genetically tested, number of transfers, and the cumulative chance that has accrued. If the threshold has not been crossed, we say so.
2. Re-read the cycles, not just the results. What was transferred, at what stage and grade, on what endometrial preparation, with what progesterone support, and what the fertilisation and blastocyst conversion rates were.
3. Assess the cavity properly, once. Transvaginal and 3D ultrasound; hysteroscopy where imaging suggests a reason for it — polyps, submucous fibroids, adhesions, suspected adenomyosis or endometrial polyps — not as a routine after every failure.
4. Check the things that are cheap, indicated and correctable. Endometrial thickness and estradiol exposure, progesterone levels and absorption, thyroid function, chronic endometritis, lifestyle factors in both partners.
5. Address the embryo question honestly. Where age and history make aneuploidy the most probable explanation, that conversation happens directly, including what PGT-A can and cannot tell you.
6. Decline what is not indicated, and explain why. The tests and treatments in the not-recommended lists above are not offered as a routine RIF panel at Wellspring, and the reason is given to the couple in writing.

What Are the Limitations You Should Understand?

• RIF is not a diagnosis. It is a signal to investigate. A full investigation frequently finds nothing, and that outcome is common rather than exceptional.
• A negative investigation is not a failed investigation. It rules out the treatable causes, which changes what happens next.
• Most published RIF research studied populations that would not meet the current definition. This is why so many interventions have supportive-looking studies and no convincing effect on live birth.
• No intervention has been shown to reliably overcome unexplained RIF. Any clinic presenting one as proven is ahead of the evidence.
• Age remains the strongest single determinant. It is also the one no add-on modifies.
• Continuing with further transfers is a legitimate plan, and for many couples it is the plan with the best evidence behind it.

When Should You Seek a Second Opinion?

A review is reasonable if you have had two or more failed transfers of good-quality embryos, particularly if the embryos were genetically tested; if you have been offered an immune or microbiome test panel without being told which guideline supports it; if the same protocol has been repeated without anyone re-examining the uterine cavity; if a biochemical pregnancy has been recorded as simply another failure; or if no one has explained what your cumulative chance of conceiving actually was across the cycles you have had.

Bring the complete record — stimulation protocol, embryology reports with grades, endometrial preparation and thickness, progesterone levels, and any test results already done. A RIF assessment without the previous cycle data is guesswork.

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