Unexplained recurrent implantation failures: Predictive factors of pregnancy and therapeutic management from a French multicentre study

Is there a treatable cause of repeated implantation failure, or is it simply treatment failure by chance?

RESEARCH QUESTION

Does repeated implantation failure (RIF) sometimes have a cause, or is it simply treatment failure by chance?

DESIGN

A hypothetical model of a cohort of 1000 women undergoing four repeated IVF attempts was constructed. A proportion of women with RIF carried an underlying risk factor negatively affecting implantation, compared with women without the factor. In strategy A, women had standard IVF without additional treatment; in strategy B, the women received standard IVF plus an additional treatment. The sensitivity analysis varied the prevalence of the underlying risk factor from 5% to 50%. The model was compared with literature studies where a treatment strategy had been applied.

RESULTS

With strategy A, the clinical pregnancy rate decreased with subsequent IVF attempts (31% in the first transfer with a risk factor prevalence of 5%, to 8% in the fourth transfer with a risk factor prevalence of 50%). As the prevalence increased, the clinical pregnancy rate was higher with strategy A. For strategy B, the clinical pregnancy rates for the modelled cohort decreased with each subsequent IVF attempt. Regardless of the prevalence of the risk factor, the decline in clinical pregnancy rate was less strong (from 32% in the first transfer with a prevalence of 5%, to 25% in the fourth transfer with a prevalence of 50%). When applying the model to the literature studies, the trends expected for strategy B (decreasing clinical pregnancy rates) were not expressed.

CONCLUSIONS

RIF might therefore be of iatrogenic origin due to the low success rate of IVF and might be triggered by the increasing female age associated with higher numbers of RIF.

ESHRE good practice recommendations on recurrent implantation failure

STUDY QUESTION

How should recurrent implantation failure (RIF) in patients undergoing ART be defined and managed?

SUMMARY ANSWER

This is the first ESHRE good practice recommendations paper providing a definition for RIF together with recommendations on how to investigate causes and contributing factors, and how to improve the chances of a pregnancy.

WHAT IS KNOWN ALREADY

RIF is a challenge in the ART clinic, with a multitude of investigations and interventions offered and applied in clinical practice, often without biological rationale or with unequivocal evidence of benefit.

STUDY DESIGN SIZE DURATION

This document was developed according to a predefined methodology for ESHRE good practice recommendations. Recommendations are supported by data from the literature, if available, and the results of a previously published survey on clinical practice in RIF and the expertise of the working group. A literature search was performed in PubMed and Cochrane focussing on 'recurrent reproductive failure', 'recurrent implantation failure', and 'repeated implantation failure'.

PARTICIPANTS/MATERIALS SETTING METHODS

The ESHRE Working Group on Recurrent Implantation Failure included eight members representing the ESHRE Special Interest Groups for Implantation and Early Pregnancy, Reproductive Endocrinology, and Embryology, with an independent chair and an expert in statistics. The recommendations for clinical practice were formulated based on the expert opinion of the working group, while taking into consideration the published data and results of the survey on uptake in clinical practice. The draft document was then open to ESHRE members for online peer review and was revised in light of the comments received.

MAIN RESULTS AND THE ROLE OF CHANCE

The working group recommends considering RIF as a secondary phenomenon of ART, as it can only be observed in patients undergoing IVF, and that the following description of RIF be adopted: 'RIF describes 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 and/or interventions'. It was agreed that the recommended threshold for the cumulative predicted chance of implantation to identify RIF for the purposes of initiating further investigation is 60%. When a couple have not had a successful implantation by a certain number of embryo transfers and the cumulative predicted chance of implantation associated with that number is greater than 60%, then they should be counselled on further investigation and/or treatment options. This term defines clinical RIF for which further actions should be considered. Nineteen recommendations were formulated on investigations when RIF is suspected, and 13 on interventions. Recommendations were colour-coded based on whether the investigations/interventions were recommended (green), to be considered (orange), or not recommended, i.e. not to be offered routinely (red).

LIMITATIONS REASONS FOR CAUTION

While awaiting the results of further studies and trials, the ESHRE Working Group on Recurrent Implantation Failure recommends identifying RIF based on the chance of successful implantation for the individual patient or couple and to restrict investigations and treatments to those supported by a clear rationale and data indicating their likely benefit.

WIDER IMPLICATIONS OF THE FINDINGS

This article provides not only good practice advice but also highlights the investigations and interventions that need further research. This research, when well-conducted, will be key to making progress in the clinical management of RIF.

STUDY FUNDING/COMPETING INTERESTS

The meetings and technical support for this project were funded by ESHRE. N.M. declared consulting fees from ArtPRED (The Netherlands) and Freya Biosciences (Denmark); Honoraria for lectures from Gedeon Richter, Merck, Abbott, and IBSA; being co-founder of Verso Biosense. He is Co-Chief Editor of Reproductive Biomedicine Online (RBMO). D.C. declared being an Associate Editor of Human Reproduction Update, and declared honoraria for lectures from Merck, Organon, IBSA, and Fairtility; support for attending meetings from Cooper Surgical, Fujifilm Irvine Scientific. G.G. declared that he or his institution received financial or non-financial support for research, lectures, workshops, advisory roles, or travelling from Ferring, Merck, Gedeon-Richter, PregLem, Abbott, Vifor, Organon, MSD, Coopersurgical, ObsEVA, and ReprodWissen. He is an Editor of the journals Archives of Obstetrics and Gynecology and Reproductive Biomedicine Online, and Editor in Chief of Journal Gynäkologische Endokrinologie. He is involved in guideline developments and quality control on national and international level. G.L. declared he or his institution received honoraria for lectures from Merck, Ferring, Vianex/Organon, and MSD. He is an Associate Editor of Human Reproduction Update, immediate past Coordinator of Special Interest Group for Reproductive Endocrinology of ESHRE and has been involved in Guideline Development Groups of ESHRE and national fertility authorities. D.J.M. declared being an Associate Editor for Human Reproduction Open and statistical Advisor for Reproductive Biomedicine Online. B.T. declared being shareholder of Reprognostics and she or her institution received financial or non-financial support for research, clinical trials, lectures, workshops, advisory roles or travelling from support for attending meetings from Ferring, MSD, Exeltis, Merck Serono, Bayer, Teva, Theramex and Novartis, Astropharm, Ferring. The other authors had nothing to disclose.

DISCLAIMER

This Good Practice Recommendations (GPR) document represents the views of ESHRE, which are the result of consensus between the relevant ESHRE stakeholders and are based on the scientific evidence available at the time of preparation. ESHRE GPRs should be used for information and educational purposes. They should not be interpreted as setting a standard of care or be deemed inclusive of all proper methods of care, or be exclusive of other methods of care reasonably directed to obtaining the same results. They do not replace the need for application of clinical judgement to each individual presentation, or variations based on locality and facility type. Furthermore, ESHRE GPRs do not constitute or imply the endorsement, or favouring, of any of the included technologies by ESHRE.

Association between endometrial senescent cells and immune cells in women with repeated implantation failure

PURPOSE

The aim of this study was to compare women with recurrent implantation failure (RIF) and control group in terms of the associations between p16-positive senescent cells and certain types of immune cells in human endometrium during the mid-luteal phase METHODS: Immunohistochemical staining was performed in 116 endometrial biopsies taken from 57 women presenting RIF, and control group of 59 women who became pregnant after the first intracytoplasmic sperm injection. Endometrial tissue sections were stained immunohistochemically for p16 (Senescent cells), CD4 (T-helpers), CD8 (T-killers), CD14 (Monocytes), CD68 (Macrophages), CD56 (Natural killers), and CD79α (B-cells). The percentage of positively stained cells for each marker was calculated by HALO image analysis software. The quantity and the relationship between senescent cells and immune cells were assessed and compared between the two groups.

RESULTS

The correlation coefficient was highest between senescent cells and CD4+ cells and was lowest between senescent cells and CD14+ cells in RIF women, similarly to the control group. However, most of the observed correlations among senescent and immune cells weaken notably or disappear in the RIF group. When comparing senescent cell-to-immune cell quantitative ratios, only p16+/CD4+ cell ratio was significantly higher in RIF women as compared with patients from the control group.

CONCLUSION

Our study indicates that the quantity of senescent cells in human endometrium during the mid-luteal phase has the strongest association with the amount of T helpers. Moreover, the specificity of this association might have an important impact on the occurrence of RIF.

Prednisone vs Placebo and Live Birth in Patients With Recurrent Implantation Failure Undergoing In Vitro Fertilization: A Randomized Clinical Trial

Importance

Implantation failure remains a critical barrier to in vitro fertilization. Prednisone, as an immune-regulatory agent, is widely used to improve the probability of implantation and pregnancy, although the evidence for efficacy is inadequate.

Objective

To determine the efficacy of 10 mg of prednisone compared with placebo on live birth among women with recurrent implantation failure.

Design, Setting, and Participants

A double-blind, placebo-controlled, randomized clinical trial conducted at 8 fertility centers in China. Eligible women who had a history of 2 or more unsuccessful embryo transfer cycles, were younger than 38 years when oocytes were retrieved, and were planning to undergo frozen-thawed embryo transfer with the availability of good-quality embryos were enrolled from November 2018 to August 2020 (final follow-up August 2021).

Interventions

Participants were randomized (1:1) to receive oral pills containing either 10 mg of prednisone (n = 357) or matching placebo (n = 358) once daily, from the day at which they started endometrial preparation for frozen-thawed embryo transfer through early pregnancy.

Main Outcomes and Measures

The primary outcome was live birth, defined as the delivery of any number of neonates born at 28 or more weeks' gestation with signs of life.

Results

Among 715 women randomized (mean age, 32 years), 714 (99.9%) had data available on live birth outcomes and were included in the primary analysis. Live birth occurred among 37.8% of women (135 of 357) in the prednisone group vs 38.8% of women (139 of 358) in the placebo group (absolute difference, -1.0% [95% CI, -8.1% to 6.1%]; relative ratio [RR], 0.97 [95% CI, 0.81 to 1.17]; P = .78). The rates of biochemical pregnancy loss were 17.3% in the prednisone group and 9.9% in the placebo group (absolute difference, 7.5% [95% CI, 0.6% to 14.3%]; RR, 1.75 [95% CI, 1.03 to 2.99]; P = .04). Of those in the prednisone group, preterm delivery occurred among 11.8% and of those in the placebo group, 5.5% of pregnancies (absolute difference, 6.3% [95% CI, 0.2% to 12.4%]; RR, 2.14 [95% CI, 1.00 to 4.58]; P = .04). There were no statistically significant between-group differences in the rates of biochemical pregnancy, clinical pregnancy, implantation, neonatal complications, congenital anomalies, other adverse events, or mean birthweights.

Conclusions and Relevance

Among patients with recurrent implantation failure, treatment with prednisone did not improve live birth rate compared with placebo. Data suggested that the use of prednisone may increase the risk of preterm delivery and biochemical pregnancy loss. Our results challenge the value of prednisone use in clinical practice for the treatment of recurrent implantation failure.

Trial Registration

Chinese Clinical Trial Registry Identifier: ChiCTR1800018783.

Is glucocorticoid use associated with a higher clinical pregnancy rate of in vitro fertilization and embryo transfer? A meta-analysis

Background

It has been reported that the use of glucocorticoids may be able to improve clinical pregnancy rates in patients receiving in vitro fertilization and embryo transfer (IVF-ET). The purpose of this study was to investigate the association between glucocorticoid use and clinical pregnancy rate in IVF-ET patients.

Methods

This study has been registered on the International Register of Prospective Systems Evaluation (PROSPERO) (ID: CRD42022375427). A thorough and detailed search of databases including PubMed, Web of Science, Embase, and Cochrane Library was conducted to identify eligible studies up to October 2022. Quality assessment was conducted on the modified Jadad Scoring Scale and Newcastle-Ottawa Scale, and the inter-study heterogeneity was estimated by Q test and I² test. Combined hazard ratios with 95% CI were calculated using random effects or fixed effects models based on heterogeneity. Meanwhile, Begg's and Egger's tests were used to detect the existence of publication bias, the leave-one-out method was used for sensitivity analysis and multiple subgroup analyses were conducted.

Results

Seventeen studies involving 3056 IVF-ET cycles were included. We found that glucocorticoid use was associated with a higher IVF-ET pregnancy rate (OR = 1.86, 95% CI = 1.27-2.74, P = 0.002). In the subgroup analysis, studies of different regions and different study types all showed similar results that glucocorticoid is beneficial to improve the clinical pregnancy rate of patients with IVF-ET, and patients with positive autoantibodies and patients receiving IVF-ET multiple times also showed the same results. However, there was no significant change in clinical pregnancy rates in the seven studies with negative autoantibodies and in the seven studies with initial IVF-ET treatment. The results of the 12 medium-acting glucocorticoids and 4 long-acting glucocorticoids were also generally consistent with each other. There was no statistical difference in subgroup analysis of whether patients had endometriosis or not.

Conclusion

Appropriate use of glucocorticoids is beneficial for improving the clinical pregnancy rate in women receiving IVF-ET, but this result still needs to be verified by more high-quality and large sample size randomized controlled trials (RCTs).

Endometrial Staining of CD56 (Uterine Natural Killer), BCL-6, and CD138 (Plasma Cells) Improve Diagnosis and Clinical Pregnancy Outcomes in Unexplained Infertility and Recurrent IVF Failures: Standardization of Diagnosis with Digital Pathology

In women with unexplained infertility (UI) and recurrent in vitro fertilization (IVF) failures, the etiology is often unclear. Endometrial immune perturbations and the use of immune markers associated with these dysregulations are of great interest in the diagnosis and treatment of UI. However, reliable biomarkers and standardized quantification methods are lacking. Here, to address endometrial immune dysregulation in UI patients with recurrent IVF failures, we performed endometrial tissue sampling and immunostaining of CD56 (uNK), CD138, and BCL-6. Of these cases, 57.9% had positive CD56 in the endometrial stroma, while 46.1% had positive BCL-6 in the glandular epithelium, and 14.5% of the cases were found to be positive for CD138. Combined staining rates were 60.5%, 68.4%, and 71.05% for (CD56 or BCL-6), (CD56 or CD138), and (CD56, BCL-6, or CD138), respectively. There was a significant correlation between CD56 and BCL-6 positivity, while CD138 positivity was an independent parameter. After the recommended targeted therapy, pregnancy rates were found to increase from 58.5% to 61.6% and 73.8% in CD56-positive, (CD56- or BCL-6-positive), and (CD56-, BCL-6-, or CD138-positive) cases, respectively. Notably, a retrospective evaluation of digital pathology and light microscopy results showed a significant correlation. This study suggests that the examination of CD56, BCL-6, and CD138 in the same endometrial sample may be an effective method in determining the etiology of UI and reaching an early diagnosis and treatment options. Moreover, digital pathology can be used in the evaluation of CD56 and BCL-6 to provide objective, rapid, and reliable results.

The effectiveness of immunomodulatory therapies for patients with repeated implantation failure: a systematic review and network meta-analysis

This meta-analysis analyzed the clinical pregnancy outcomes of repeated implantation failure (RIF) patients treated with immunomodulatory therapies. Publications (published by August 16, 2021) were identified by searching the PubMed, Embase, and Web of Science databases. The quality of the studies was evaluated with the Cochrane bias risk assessment tool, and a network meta-analysis was performed with Stata 14.0. The outcomes were clinical pregnancy rate (CPR), live birth rate (LBR), and implantation rate (IR). The results of our network meta-analysis of 16 RCTs (including 2,008 participants) show that PBMCs, PRP, and SC-GCSF can significantly improve the CPR compared with LMWH (PBMCs: OR 2.15; 95% CI 1.21-3.83; PRP: OR 2.38; 95% CI 1.08-5.24; SC-GCSF: OR 2.46; 95% CI 1.05-5.72). The LBR of PRP was significantly higher than those of IU-GCSF (OR 3.81; 95% CI 1.22-11.86), LMWH (OR 4.38; 95% CI 1.50-12.90), and intralipid (OR 3.85; 95% CI 1.03-14.29), and the LBR of PBMCs was also significantly better than that of LMWH (OR 2.35; 95% CI 1.14-4.85). Furthermore, PRP treatment significantly improved the IR compared with LMWH treatment (OR 2.81; 95% CI 1.07-7.4). The limited evidence from existing RCTs suggests that PBMCs and PRP are the best therapeutic options for RIF patients. However, owing to the quantity limitation, more top-quality research is required to obtain additional high-level evidence.

Effectiveness of herb-partitioned moxibustion on the navel for pregnancy outcomes in patients with recurrent implantation failure undergoing in vitro fertilization and embryo transfer: a study protocol for a randomized controlled trial

Background

Recurrent implantation failure (RIF) in the majority of patients undergoing in vitro fertilization and embryo transfer (IVF-ET) is caused by various factors such as maternal age, embryo quality, endometrial receptivity (ER), and immunity. The incidence of RIF is usually between 5 and 10%. Previous studies have shown that herb-partitioned moxibustion on the navel is one of the treatment methods of acupuncture with a positive effect on pregnancy. However, its application in the treatment of RIF has not been reported. Therefore, this study aims to evaluate the effectiveness and safeness of herb-partitioned moxibustion on the navel in improving the outcome of frozen embryo transfer (FET) in patients with RIF.

Methods

This study conducts a randomized controlled trial (RCT). It is planned to recruit 210 patients undergoing RIF for FET from Affiliated Hospital of Shandong University of Traditional Chinese Medicine and randomly divide them into the treatment group and the control group in a ratio of 1:1. The patient of the treatment group will be treated with herb-partitioned moxibustion on the navel once a week for three consecutive menstrual cycles. No intervention will be used in the control group for 3 menstrual cycles. In the fourth menstrual cycle, all patients will undergo artificial cycle to prepare the endometrium for FET. The pregnancy outcomes will be recorded after a 3-month follow-up. Primary outcome will be assessed as the ongoing pregnancy rate compared with the control group. Secondary outcomes include the endometrial type, resistance index (RI), pulsatility index (PI) of the bilateral uterine artery, endometrial blood flow, serum estradiol (E₂), progesterone (P), biochemical pregnancy rate, implantation rate, and clinical pregnancy rate.

Discussion

If the results show that the herb-partitioned moxibustion on the navel can improve IVF-ET outcomes in patients with RIF, it will be recommended in clinical practice.

Trial registration

Chinese Clinical Trial Registry (ChiCTR) ChiCTR2100043954. Registered on 8 July 2021.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06156-5.

The Role of Interleukins in Recurrent Implantation Failure: A Comprehensive Review of the Literature

Recurrent implantation failure (RIF) is a multifactorial condition affecting 10-15% of in vitro fertilization (IVF) couples. Data suggest that functional dysregulation of the endometrial immune system constitutes one of the main pathophysiological mechanisms leading to RIF. The aim of this article is to provide a thorough presentation and evaluation of the role of interleukins (ILs) in the pathogenesis of RIF. A comprehensive literature screening was performed summarizing current evidence. During implantation, several classes of ILs are secreted by epithelial and stromal endometrial cells, including IL-6, IL-10, IL-12, IL-15, IL-18, and the leukemia inhibitory factor. These ILs create a perplexing network that orchestrates both proliferation and maturation of uterine natural killer cells, controls the function of regulatory T and B cells inhibiting the secretion of antifetal antibodies, and supports trophoblast invasion and decidua formation. The existing data indicate associations between ILs and RIF. The extensive analysis performed herein concludes that the dysregulation of the ILs network indeed jeopardizes implantation leading to RIF. This review further proposes a mapping of future research on how to move forward from mere associations to robust molecular data that will allow an accurate profiling of ILs in turn enabling evidence-based consultancy and decision making when addressing RIF patients.

Mild infection induced by low-dose LPS does not impair follicular development and is beneficial to pregnancy in mice

The reproductive tract is susceptible to infection by a variety of bacteria, which can impair ovarian and uterine function. However, there is little known about whether mild infection can harm follicle development and embryo implantation. Here our results showed that the immune response to a mild infection simulated by low-dose LPS induced inflammatory factor IL-1b expression and decreased MMP2 expression involved in embryo implantation. LPS treatment also inhibited the ovulation process and reduced litter weight. Despite the immune response and the disturbed ovulation induced by treatment with low-dose LPS, the overall result was beneficial to mouse pregnancy. This research provides the necessary foundation for exploring the effects of mild bacterial infection on ovarian and uterine function in mammals.

Biomolecular Markers of Recurrent Implantation Failure-A Review

Currently, infertility affects 8–12% of reproductive age couples worldwide, a problem that also affects women suffering from recurrent implantation failure (RIF). RIF is a complex condition resulting from many physiological and molecular mechanisms involving dynamic endometrium–blastocyst interaction. The most important are the endometrial receptivity process, decidualization, trophoblast invasion, and blastocyst nesting. Although the exact multifactorial pathogenesis of RIF remains unclear, many studies have suggested the association between hormone level imbalance, disturbances of angiogenic and immunomodulatory factors, certain genetic polymorphisms, and occurrence of RIF. These studies were performed in quite small groups. Additionally, the results are inconsistent between ethnicities. The present review briefly summarizes the importance of factors involved in RIF development that could also serve as diagnostic determinants. Moreover, our review could constitute part of a new platform for discovery of novel diagnostic and therapeutic solutions for RIF.