“A Battery of Tests and Injections After Two or Three Failed Transfers?… ASRM Cites ‘Lack of Evidence’”
- True RIF Requires 3 to 6 Failed Euploid Transfers: ASRM definition requires failing enough transfers to cross a 95% cumulative pregnancy probability threshold, putting the brakes on premature RIF labeling
- ERA Lacks Evidence for Routine Use, Endometrial Scratching Not Recommended: High-profile add-ons fail to demonstrate live birth improvements in large-scale randomized trials
- Immunological Therapies (IVIG, Intralipid, G-CSF) and PRP Lack Sufficient Clinical Justification: Routine antiphospholipid screening, empiric heparin, and BCL-6 testing also discouraged
- “Continuing Sequential Transfers Is a Rational Strategy”: Unexplained transfer failures do not warrant endless unproven add-ons when anatomical and clinical basics are addressed
The clinical practice of immediately diagnosing a patient with Recurrent Implantation Failure (RIF) after one or two unsuccessful embryo transfers—and subsequently ordering a battery of tests including the Endometrial Receptivity Analysis (ERA), endometrial scratching, immunological panels, intravenous lipid infusions, IVIG, thrombophilia screening, and empiric anticoagulants—has been directly challenged by the American Society for Reproductive Medicine (ASRM).
In an updated document titled “Recurrent implantation failure: a committee opinion,” formulated by the ASRM Practice Committee and published in the August 2026 issue of Fertility and Sterility, the society comprehensively re-evaluated the diagnostic criteria, investigative workups, and therapeutic interventions surrounding RIF.
The most notable revision centers on the diagnostic threshold: how many failed transfers constitute true RIF?
The ASRM proposed that RIF should be defined only when implantation fails after transferring a sufficient number of high-quality blastocysts to reach a ≥95% cumulative probability of pregnancy.
Based on current cumulative live birth models, for embryos confirmed to be chromosomally normal via PGT-A (euploid), a patient must experience approximately 3 to 6 failed transfers before meeting the definition of RIF. For untested embryos, the required number varies depending on maternal age.
In clinical terms: failing one or two euploid transfers provides insufficient evidence to conclude that “the endometrium is defective,” “the immune system is rejecting the embryo,” or “the window of implantation is displaced.”
Endometrial Receptivity Analysis (ERA): Lacks Evidence for Routine Use
The Endometrial Receptivity Analysis (ERA)—which profiles the expression of 248 endometrial genes to estimate the receptive window and customize progesterone timing—has been widely utilized for patients with transfer failures.
However, clinical trials evaluating whether personalized embryo transfer (pET) improves live birth rates show conflicting and largely non-supportive outcomes:
- In a 31-center randomized controlled trial of 767 women undergoing euploid embryo transfers, no statistically significant difference in live birth rates was observed between women who had personalized transfer timing based on ERA results and those who underwent standard transfer timing.
- Subsequent predictive validity analyses demonstrated an Area Under the Curve (AUC) of only 0.52 for ERA’s ability to predict implantation failure—virtually equivalent to random chance.
The ASRM committee concluded: There is insufficient evidence to support the routine use of ERA in patients with RIF.
Endometrial Scratching: Formally Not Recommended
The committee issued an even firmer stance against endometrial scratching (inducing intentional mechanical injury to the endometrium prior to transfer to provoke local cytokine and growth factor release).
While early small studies suggested potential benefit, large-scale trials failed to replicate these findings:
- In a definitive randomized trial encompassing 1,364 women, endometrial scratching failed to improve live birth rates, including within subgroups of women who had experienced two or more previous frozen embryo transfer failures.
The ASRM concluded: Endometrial injury does not appear to be effective and is not recommended as a treatment for RIF.
Immunotherapy “Packages” and Intrauterine PRP: Insufficient Clinical Evidence
When implantation fails repeatedly, patients are frequently directed toward immune panels (such as peripheral NK cell testing) followed by empirical immunomodulatory regimens:
- Intralipid Infusions & G-CSF: Evaluated as lacking sufficient evidence to warrant clinical recommendation for RIF.
- Intravenous Immunoglobulin (IVIG): Not recommended as an evidence-based treatment for RIF due to safety risks, high cost, and lack of reproducible efficacy.
- Intrauterine PRP: While exploratory studies exist, significant heterogeneity in preparation protocols, dosages, timing, and a lack of randomized controls mean current evidence is insufficient to justify its routine use in RIF.
The committee formally affirmed: There is insufficient evidence to support the routine use of immunotherapy in patients with RIF.
Antiphospholipid Syndrome (APAS) Screening and Empiric Anticoagulation
The committee also pushed back against routine screening for Antiphospholipid Antibody Syndrome (APAS) or the empiric prescription of aspirin, unfractionated heparin, or low-molecular-weight heparin (LMWH, such as enoxaparin) for unexplained implantation failure:
- No consistent epidemiological link has been established between APAS antibodies and true RIF.
- Randomized trials administering heparin or LMWH to women without confirmed thrombophilias have shown no consistent reproductive benefit.
Consequently, routine APAS testing and empiric anticoagulant therapy are not recommended for all women experiencing RIF, except when clear independent medical indications for thrombophilia management are present.
BCL-6 Testing and PGT-A in the Context of RIF
- BCL-6 Endometrial Biopsy: Used as a proxy marker for suspected occult endometriosis. The ASRM noted that literature regarding the diagnostic validity of BCL-6 and the clinical efficacy of subsequent suppression protocols remains contradictory; thus, routine BCL-6 screening in RIF is not recommended.
- PGT-A (Preimplantation Genetic Testing for Aneuploidy): While embryonic aneuploidy is a leading cause of implantation failure, there is no evidence demonstrating that performing PGT-A inherently increases cumulative live birth rates in patients with RIF. For patients with recurrent failures of untested embryos, PGT-A may be considered alongside thorough counseling to assess whether chromosomal aneuploidy was the driving cause, but it should not be marketed as a curative treatment for RIF.
The Evidence-Based Diagnostic Strategy
The ASRM guidance does not advocate abandoning diagnostic evaluations altogether. Rather, it outlines a focused, evidence-based assessment when true RIF is suspected:
- Detailed Case Review: Re-evaluating maternal age, detailed clinical history, previous stimulation protocols, embryo developmental grades, and transfer mechanics.
- Anatomical and Cavitary Assessment: Evaluating the uterine cavity and fallopian tubes using saline infusion sonohysterography (SHG), diagnostic hysteroscopy, hysterosalpingography (HSG), or 3D transvaginal ultrasound. Correcting identifiable mechanical impediments (e.g., endometrial polyps, submucosal fibroids, intrauterine adhesions, or hydrosalpinx) is strongly supported.
- Parental Karyotyping: Recommended in selected cases to rule out balanced chromosomal translocations.
Clinical Takeaways: Continuing Transfers as a Rational Strategy
The core message of the ASRM opinion is that “active management” does not require ordering every unvalidated test and empirical medication available.
When a comprehensive history and anatomical evaluation reveal no correctable pathology, endlessly expanding testing panels is not clinically justified. Because mathematical models confirm that many patients will achieve pregnancy on subsequent attempts, continuing sequential embryo transfers remains a medically sound and evidence-based management strategy.
A failed transfer is emotionally taxing, often creating pressure to “add something new.” However, the ASRM document clarifies that distinguishing true biological failure from expected statistical variation—and adhering to therapies backed by robust randomized evidence—remains the gold standard in reproductive medicine.
※ This article was synthesized based on the Practice Committee Opinion “Recurrent implantation failure: a committee opinion” published by the American Society for Reproductive Medicine (ASRM) in Fertility and Sterility (August 2026 issue). It does not replace individualized medical advice, clinical diagnosis, or treatment, and specific medical decisions should always be made in consultation with a qualified reproductive endocrinologist.
※ The images associated with this article were generated using generative AI (ChatGPT, OpenAI) as visual references and do not depict real individuals.