Determining diagnostic criteria and cause of recurrent implantation failure

The effect of sequential embryo transfer on pregnancy outcomes in patients with recurrent implantation failure: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

The aim of our study was to assess the impact of sequential embryo transfer on pregnancy outcomes among patients with recurrent implantation failure (RIF).

METHODS

We conducted a comprehensive search across various databases for eligible clinical trials from inception to January 2024. Randomized controlled trials (RCTs) were included if they compared sequential embryo transfer, comprising both cleavage-stage and blastocyst-stage embryos, with other transfer protocols in infertile women with repeated implantation failure. Meta-analysis was performed using Revman software. Our primary focus was on the ongoing pregnancy rate. Our secondary measures included rates of chemical pregnancies, clinical pregnancies, miscarriages, and multiple pregnancies.

RESULTS

Seven RCTs, encompassing 909 patients, met the inclusion criteria. Sequential embryo transfer demonstrated a significant increase in the ongoing pregnancy rate compared to the control group (OR = 2.28, 95% CI [1.46, 3.56], p = 0.003). Moreover, the sequential embryo transfer group exhibited notable improvements in chemical and clinical pregnancy rates. There were no statistically significant differences between the groups regarding multiple pregnancy and miscarriage rates (p > 0.05).

CONCLUSIONS

Sequential embryo transfer shows promise in enhancing pregnancy outcomes among RIF patients. However, additional trials are warranted to validate our findings.

Innate and adaptive immune dysregulation in women with recurrent implantation failure

Recurrent implantation failure (RIF) is a condition where a woman fails to obtain pregnancy after multiple embryo transfer cycles, even with superior-quality blastocysts. There are various factors that can contribute to RIF, including immunologic disturbances. The immune system is extremely important during pregnancy. Immune cells such as T cells, B cells, natural killer (NK) cells, and macrophages (MQ) are present in the female reproductive tract and are accountable for regulating the immune response to invading pathogens and maintaining tissue homeostasis. Dysregulation of these immune cells can lead to inflammation, which can impair fertility. One of the most common immunological disturbances observed in RIF is an altered Th1/Th2 ratio, along with changes in NK cell and macrophage numbers. In addition, the presence of some antibodies, such as anti-ovarian antibodies, can also contribute to RIF. Interleukins have been implicated in the development of an inflammatory response that can interfere with successful embryo implantation. As a result, a comprehensive understanding of immunological compartments in RIF women could assist us in determining the immunological origins of this disease. We will discuss immunological factors that might contribute to RIF etiology, including cellular and molecular components.

Comprehensive analysis of circRNA-miRNA-mRNA network related to angiogenesis in recurrent implantation failure

BACKGROUND

Abnormal endometrial blood flow causes a decrease in endometrial receptivity and is considered a relatively independent risk factor for recurrent implantation failure (RIF). This study aimed to explore the potentially functional circRNA-miRNA-mRNA network in RIF, and further explore its mechanism.

METHODS

Datasets were downloaded from the GEO database to identify differentially expressed circRNAs, miRNAs and mRNAs. The circRNA-miRNA-mRNA and PPI networks were constructed using Cytoscape 3.6.0 and the STRING database, the hub genes were identified with the cytoHubba plug-in, and a circRNA-miRNA-hub mRNA regulatory sub-network was constructed. Then, GO and KEGG pathway enrichment analyses of the hub genes were performed to comprehensively analyze the mechanism of hub mRNAs in RIF. Due to the results of circRNAs-miRNAs-hub mRNAs regulatory network, we verified the expression of circRNA_0001721, circRNA_0000714, miR-17-5p, miR-29b-3p, HIF1A and VEGFA in the RIF mouse model by qRT‒PCR and western blotting.

RESULTS

We initially identified 175 DEmRNAs, 48 DEmiRNAs and 56 DEcircRNAs in RIF associated with angiogenesis and constructed a circRNA-miRNA‒mRNA network and PPI network. We further identified six hub genes in the acquired network. Based on these genes, functional enrichment analysis revealed that the HIF-1 signaling pathway plays a vital role in endometrial angiogenesis in RIF. In addition, the interaction networks of circRNA_0001721/miR-17-5p/HIF1A and the circRNA_0000714/miR-29b-3p/VEGFA axis were predicted. In the RIF mouse model, circRNA_0001721, circRNA_0000714, HIF1A and VEGFA were down-regulated, whereas miR-17-5p and miR-29b-3p were up-regulated according to qRT‒PCR and western blotting.

CONCLUSION

This study revealed that the HIF-1 signaling pathway plays a vital role in endometrial angiogenesis in RIF. The circRNA_0001721/miR-17-5p/HIF1A and circRNA_0000714/miR-29b-3p/VEGFA axes might play a role in the pathogenesis of endometrial angiogenesis in RIF.

Precise hourly personalized embryo transfer significantly improves clinical outcomes in patients with repeated implantation failure

Purpose

This study investigated whether RNA-Seq-based endometrial receptivity test (rsERT)-which provides precision for the optimal hour of the window of implantation (WOI)-can improve clinical outcomes of frozen embryo transfer (FET) cycles in patients with a history of repeated implantation failure (RIF).

Methods

Patients with a history of RIF who received at least one autologous high-quality blastocyst during the subsequent FET cycle were retrospectively enrolled and divided into two groups: rsERT and FET, comprising patients who underwent rsERT-guided pET (n=115) and standard FET without rsERT (n=272), respectively.

Results

In the rsERT group, 39.1% (45/115) of patients were receptive. rsERT patients showed a higher probability of achieving both positive human chorionic gonadotropin (63.5% vs. 51.5%, P=0.03) and clinical pregnancy (54.8% vs. 38.6%, P=0.003) rates. In subgroup analysis, rsERT patients with non-receptive results had higher clinical pregnancy rates than patients undergoing FET (58.6% vs. 38.6%, P=0.003). rsERT patients with receptive results guided by rsERT with a precise WOI time had higher, although non-significant, clinical pregnancy rates (48.9% vs. 38.6%, P=0.192) than patients who underwent standard-time FET.

Conclusion

Hourly precise rsERT can significantly improve the probability of achieving clinical pregnancy in patients with RIF, especially in those with non-receptive rsERT results.

Factors Affecting the Potential Efficacy of Intrauterine Platelet-Rich Plasma Infusion on Thin Endometrium in Women with Recurrent Implantation Failure

Optimizing endometrial thickness (EMT) is crucial for successful embryo implantation, but enhancing thin endometrium remains a significant challenge. Platelet-rich plasma (PRP)-derived therapies have emerged as a promising approach in reproductive medicine due to their capacity to facilitate tissue repair and regeneration. This study aims to identify the risk factors associated with the failure of intrauterine PRP infusion for thin endometrium in women with recurrent implantation failure (RIF). We retrospectively reviewed data from 77 women with RIF, all exhibiting an EMT of <7 mm. These women underwent programmed hormone therapy for frozen embryo transfer (FET) and received two autologous intrauterine PRP infusions. Following intrauterine PRP-lysate (PL) infusions, the mean increase in EMT was 1.9 ± 1.2 mm, with EMT reaching 7 mm in 86% of the cases (66/77; average EMT, 8.3 mm). We identified an exceedingly thin EMT as a risk factor impacting the therapeutic efficacy in increasing EMT (p = 0.04, OR: 3.16; 95% CI: 1.03-9.67). Additionally, the number of previous uterine surgeries emerged as a prognostic factor for pregnancy failure following PL infusion (p = 0.02, OR: 2.02; 95% CI: 1.12-3.64). Our findings suggest that an extremely thin EMT and a history of numerous uterine surgeries can impede successful pregnancy, even when an optimal EMT is achieved following PRP infusion.

Impact of thyroid autoimmunity on pregnancy outcomes in euthyroid patients with recurrent implantation failure

RESEARCH QUESTION

Does thyroid autoimmunity (TAI) adversely affect pregnancy outcomes after IVF/intracytoplasmic sperm injection (ICSI) in euthyroid patients with recurrent implantation failure (RIF)?

DESIGN

This retrospective cohort study was conducted at the Reproductive Hospital Affiliated with Shandong University from November 2016 to September 2021. A total of 1031 euthyroid patients diagnosed with RIF were enrolled. Based on serum thyroid autoantibody concentrations, the participants were divided into two groups: the TAI-positive group (219 women with RIF) and the TAI-negative group (812 women with RIF). The parameters were compared between the two groups. Additionally, logistic regression was used to adjust related confounders for primary outcomes, and subgroup and stratified analyses were performed according to different thyroid autoantibody types and TSH concentrations.

RESULTS

There was no significant difference in ovarian reserve, ovarian response, embryo quality, pregnancy outcome or neonatal outcome between the two groups (P > 0.05). After adjustments for age, body mass index, thyroid-stimulating hormone and free thyroxine, the biochemical pregnancy rate in the TAI-positive group was significantly lower than that in the TAI-negative group (odds ratio 1.394, 95% CI 1.023-1.901, adjusted P = 0.036). Regarding the implantation rate, clinical pregnancy rate, pregnancy loss rate, stillbirth rate and live birth rate, no significant differences were observed even with subgroup and stratified analyses (P > 0.05).

CONCLUSIONS

TAI had no impact on pregnancy outcomes in euthyroid RIF patients who underwent IVF/ICSI. In clinical practice, interventions targeting thyroid autoantibodies in these patients should be implemented with caution and additional evidence is needed.

The impact of the use of immunosuppressive treatment after an embryo transfer in increasing the rate of live birth

The tolerance of the immune system for the semi-allogeneic embryo is promoted by several factors and the cells involved in the immune system and factors in the mother during pregnancy. The dysregulation of the immune responses between the mother and fetus is a risk factor that raises the likelihood of rejection of the embryo and reproductive failure. To safeguard embryos and prevent immunological attacks, it is critical to suppress immunological rejection and encourage immunological tolerance. Based on current medical literature, it seems that immune cell management through immunosuppressive therapies can address reproductive failures. Immunosuppressive treatment has demonstrated encouraging results in terms of enhancing outcomes related to pregnancy and rates of live birth by regulating the immune responses of mothers and positively impacting the reproductive processes of humans. Currently, there is scarcity of high-quality data regarding the safety and efficacy of immunosuppressive therapies for children and mothers. Therefore, it is important to exercise caution while selecting use of any immunosuppressive therapy in pregnancy. This mini review provides a comprehensive overview of the existing literature regarding the impact of Calcineurin Inhibitors and anti-TNF treatment on improving the live birth rate following embryo transfer.

Efficacy of atosiban for repeated implantation failure in frozen embryo transfer cycles

Atosiban was commonly added to improve pregnancy outcomes of patients with repeated embryo implantation failure (RIF). In this study, we aimed to investigate the effect of atosiban before transferring the frozen-thawed embryo to RIF patients. This retrospective study was conducted in the Hospital for Reproductive Medicine affiliated to Shandong University from August 2017 to June 2021. A total of 1774 women with a history of RIF undergoing frozen embryo transfer (FET) were included in this study. All the participants were classified into atosiban or control group: Group A included 677 patients who were administered atosiban intravenously 30 min prior to FET with a dose of 37.5 mg; Group B included 1097 patients who received no atosiban before the transfer. There were no significant differences observed in the live birth rate (LBR) (39.73% vs. 39.02%, P = 0.928) between the two groups. Other secondary outcomes including biochemical pregnancy rate, clinical pregnancy rate, implantation rate, clinical miscarriage rate and preterm birth rate were similar between the two groups (all P > 0.05). However, subgroup analysis demonstrated significantly higher preterm birth rates in the control group compared with the atosiban group (0 versus 3.0%, P = 0.024) in the natural FET cycles. Atosiban may not improve pregnancy outcomes of RIF patients in FET cycles. However, the effects of Atosiban on pregnancy outcomes should be assessed in clinical trials with larger sample sizes.

Immunomodulation for unexplained recurrent implantation failure: where are we now?

In brief

Immune dysfunction may contribute to or cause recurrent implantation failure. This article summarizes normal and pathologic immune responses at implantation and critically appraises currently used immunomodulatory therapies.

Abstract

Recurrent implantation failure (RIF) may be defined as the absence of pregnancy despite the transfer of ≥3 good-quality blastocysts and is unexplained in up to 50% of cases. There are currently no effective treatments for patients with unexplained RIF. Since the maternal immune system is intricately involved in mediating endometrial receptivity and embryo implantation, both insufficient and excessive endometrial inflammatory responses during the window of implantation are proposed to lead to implantation failure. Recent strategies to improve conception rates in RIF patients have focused on modulating maternal immune responses at implantation, through either promoting or suppressing inflammation. Unfortunately, there are no validated, readily available diagnostic tests to confirm immune-mediated RIF. As such, immune therapies are often started empirically without robust evidence as to their efficacy. Like other chronic diseases, patient selection for immunomodulatory therapy is crucial, and personalized medicine for RIF patients is emerging. As the literature on the subject is heterogenous and rapidly evolving, we aim to summarize the potential efficacy, mechanisms of actions and side effects of select therapies for the practicing clinician.

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.

Chronic endometritis in recurrent implantation failure: Use of prednisone and IVF outcome

In recurrent implantation failure patients (RIF), the main criteria for diagnosis of chronic endometritis, is the presence of plasma cells CD138⁺ in endometrial biopsy. The aim of the present study was to evaluate if treatment with prednisone, in patients with RIF and chronic endometritis, improve IVF outcome. A retrospective study was performed between 2019 and 2020. A total of 27 patients with RIF and an endometrial biopsy positive for CD56⁺ cells were enrolled. The treatment with prednisone 10 mg per day is began together with controlled ovarian stimulation (COS). Among endometrial biopsies, 13 (48.14%) were positive also for CD138 cells, and an antibiotic treatment was added. In all patients, after therapy, in the subsequent IVF cycle, the clinical pregnancy rate was 25.9% and the live birth rate was 22.2%. Analysing pregnancies according to the percentage of CD 56 cells on endometrial biopsy, the live birth rate in the subgroup of patients with marked endometritis (defined by the presence of >10% CD56⁺cells) was 29.41%, while in the subgroup with mild endometritis (CD 56 >5% and <10%) was 10%. In the subgroup with mild endometritis with CD 138 positive the live birth was 25%, while in patients with CD 138 negative no live birth were observed. In patients with RIF the count of at least two cell types (CD 138 and CD 56 cells) on endometrial biopsies is advisable. Our study suggests a benefit of prednisone and antibiotic treatment on live birth rate in a subsequent IVF cycle.

Emerging trends and frontier research on recurrent implantation failure: a bibliometric analysis

Background

Recurrent implantation failure (RIF) has been recognized to be a major obstacle to the successful application of artificial reproduction technologies. In this study, the trends in RIF research were examined through a bibliometric analysis evaluating relevant literature quantitatively and qualitatively.

Methods

A total of 1,764 publications from 2000 to 2020 were downloaded from the Web of Science Core Collection (WoSCC). Relevant articles were searched using the term "recurrent implantation failure" and other synonyms of this term. Using Excel 2013, CiteSpace V, and VOSviewer 1.6.10 software, data extracted from the literature, including countries/regions, institutions, journals, keywords, and trends, were analyzed. Next, a clustered network was constructed based on 46,718 references cited by the 1,764 publications to determine the top 10 cocited articles.

Results

The annual number of publications on RIF progressively increased over time. The highest number of publications were from the United States. Analysis of the cocited reference cluster showed that "endometrial injury", "platelet-rich plasma", "chronic endometritis" and "extracellular vesicles" were the hotspots in RIF research. Burst detection analysis of the top keywords showed that "hysteroscopy" and "improvement" are emerging research foci.

Conclusions

This study clarifies the current research status and evolution of research in the field of RIF. New therapeutic interventions designed to improve pregnancy outcomes are the focus of current research and are expected to dominate future research in the field of RIF.

Increased expression of HMGB1 in the implantation phase endometrium is related to recurrent implantation failure

BACKGROUND

Impaired endometrial receptivity was the main cause of recurrent implantation failure (RIF); however, its underlying mechanisms had not been elucidated. This study aimed to determine the expression level of high-mobility group box protein 1 (HMGB1) in the endometrium with RIF and its effect on endometrial receptivity.

METHODS AND RESULTS

Genome-wide expression profiling, real-time reverse transcription PCR, immunohistochemical staining, western blot, and in vitro assays were performed in this study. We found that HMGB1 expression was significantly decreased in the implantation phase endometrium in the control group (patients with tubal infertility and successfully achieve conception after the first embryo transfer) (P = 0.006). However, the expression levels of HMGB1 mRNA and protein were significantly upregulated during the implantation phase in endometrial tissues obtained from patients with RIF compared to that in the control group (P = 0.001), consistent with the results of the genome-wide expression profiling. Moreover, in vitro assays showed that increased expression of HMGB1 in human endometrial epithelial cells dramatically displayed a marked deficiency in supporting blastocysts and human embryonic JAR cells adhesion, which mimic the process of embryo adhesion.

CONCLUSION

These findings strongly indicated that increased HMGB1 levels suppressed the epithelial cell adhesion capability, therefore contributing to impaired endometrial receptivity in patients with recurrent implantation failure, which can be used as a target for the recognition and treatment of recurrent implantation failure in clinical practice.

Intrauterine interventions for women with two or more implantation failures: A systematic review and network meta-analysis

OBJECTIVE

To compare the effectiveness of different intrauterine interventions for women with two or more unexplained implantation failures.

DESIGN

A systematic review and network meta-analysis of randomized controlled trials (RCTs).

PATIENTS

Women with two or more implantation failures undergoing fresh or frozen embryo transfer (ET).

INTERVENTIONS

An electronic search of the following databases: Pubmed, Cochrane Central Register of Controlled Trials (CENTRAL), and Embase.

MAIN OUTCOME MEASURES

Clinical pregnancy, live birth/ongoing pregnancy, and miscarriage.

RESULTS

We included 21 RCTs(3079 women) in the network meta-analysis. The network meta-analysis showed that compared with control treatment, platelet-rich plasma(PRP), peripheral blood mononuclear cells (PBMC), granulocyte colony-stimulating factor(G-CSF), human chorionic gonadotropin(HCG), and endometrial scratch(ES) significantly increased clinical pregnancy(OR 3.78, 95% CI 2.72 to 5.25; 2.79, 95% CI 1.75 to 4.45; 1.93, 95% CI 1.37 to 2.72; 1.80, 95% CI 1.18 to 2.72; 1.75, 95% CI 1.29 to 2.36, respectively). PRP ranked the highest in improving clinical pregnancy, followed by PBMC, G-CSF, HCG, and ES. Compared with control treatment, PRP, PBMC, and ES significantly increased live birth/ongoing pregnancy (OR 5.96, 95% CI 3.38 to 10.52; OR 2.55, 95% CI 1.27 to 5.11; OR 1.70, 95% CI 1.07 to 2.69, respectively). PRP ranked the highest in improving live birth/ongoing pregnancy, followed by PBMC, and ES.

CONCLUSIONS

PRP is the most effective intrauterine intervention in improving pregnancy outcome in women with two or more implantation failures.

Alterations of Cytokine Profiles in Patients With Recurrent Implantation Failure

Serum cytokine profile and T helper (Th)1/Th2 cell balance are related to the success of embryo implantation, although not yet firmly linked to recurrent implantation failure (RIF), a repeated failure to achieve clinical pregnancy following multiple high-quality embryo transfer. In this prospective study, comprehensive bioinfomatic analysis and logistic regression analysis were used to compare the serum cytokine profiles of 41 RIF patients with those of 29 subjects with first-cycle successful pregnancy in the mid-luteal phase and to assess the alterations of cytokine profiles in patients with clinical pregnancy at five weeks post-transplantation. We found several elevated pro-inflammatory cytokines, decreased anti-inflammatory cytokines, and increased Th1/Th2 cytokine ratios in RIF patients compared to control subjects. Specifically, the receiver operating characteristic (ROC) curve generated using multiple indicators provides a high predictive value for diagnosing RIF (area under the curve [AUC] = 0.94, 95% confidence interval [CI] 0.87-1.00, P < 0.0001), with a sensitivity of 96.55% and a specificity of 87.50%. Meanwhile, at five weeks post-transplantation, patients in both groups diagnosed with clinical pregnancy exhibited increased levels of several cytokines compared with pre-pregnancy levels, and a gradual shift in Th1/Th2 balance toward Th2. These findings suggest that inflammatory serum cytokines and the predominance of Th1 cells likely contribute to RIF and possibly reflect the immune environment at the maternal-fetal interface, suggesting their value as outcome indicators in assisted reproductive therapy.

Recurrent Implantation Failure May Be Identified by a Combination of Diagnostic Biomarkers: An Analysis of Peripheral Blood Lymphocyte Subsets

BACKGROUND

Recurrent implantation failure (RIF) is a challenge during assisted reproductive technology (ART). In the present study, potential diagnostic biomarkers for the immune status of peripheral blood lymphocyte subsets in patients with RIF were analyzed, with the aim of identifying novel biomarkers that may predict RIF.

METHODS

A total of 41 participants, including 21 women with RIF and 20 fertile controls, were included in the present study. Functional analysis was performed and the cytokine status of natural killer (NK), T, CD8+ T, T helper (Th), and γδ T cells which are lymphocyte subsets in peripheral blood was measured using flow cytometry. Binary logistic regression analysis adjusted for T follicular helper 1 (Tfh1), Tfh2, Tfh17, and early NK cells was performed to determine the relationship between the peripheral blood lymphocyte subsets and RIF. Potential diagnostic biomarkers were assessed by logistic regression analysis and receiver operating characteristic curves.

RESULTS

There were significantly more Tfh1, Tfh17, and NK cells in the RIF group compared with the control group (all P < 0.05). However, the percentage of T, regulatory T (Tregs), and Tfh2 cells, as well as early inhibitory NK cells, was significantly lower in the RIF group compared with the control group (all P < 0.05). Following logistics regression analysis, Treg, Tfh17, and early inhibitory NK cells exhibited significant differences between the two groups. Combination diagnosis using these 3 biomarkers had a higher area under the curve of 0.900 (95% confidence interval: 0.808-0.992, P < 0.001) in the RIF group compared with that in the control group.

CONCLUSION

T, Tregs, Tfh1, Tfh2, Tfh17, NK cells, and early inhibitory NK cells may play important regulatory roles in embryo implantation. The combination of 3 molecular markers (Treg, Tfh17, and early inhibitory NK cells) could provide a high diagnostic value for women with RIF, thus providing novel potential biomarkers for RIF in ART. The present findings could provide a reference either for the clinical treatment of patients with RIF or for future large, well-designed studies.

Subsequent IVF outcomes following antibiotic therapy for chronic endometritis in patients with recurrent implantation failure

AIM

The aim is to identify the chronic endometritis (CE) incidence in recurrent implantation failure (RIF) patients undergoing in vitro fertilization (IVF) treatment and compare the IVF outcomes of RIF patients with CE following antibiotic therapy with RIF patients without CE. Another purpose is to compare the IVF outcomes of described RIF patients with patients undergoing the first cycle of IVF.

METHODS

In this retrospective cohort study, CE was diagnosed with CD-138 immunohistochemical staining. Among RIF patients, two groups were formed as group 1, including patients diagnosed with CE and treated by antibiotics (n = 129), and group 2, including patients without CE (n = 103). Patients with the first IVF cycle having similar infertility etiologies with RIF patients were reviewed as group 3 (n = 932).

RESULTS

CE was diagnosed in 55.6% of RIF patients. The number of oocytes retrieved was not different between groups. Implantation rates (IR) were similar after antibiotic treatment in RIF patients with or without CE. However, Group 3 had a higher IR (41.1%) than group 1 and 2 (23.1% and 30.1%, respectively) (p < 0.001). Clinical pregnancy (CPR) and live birth rates (LBR) were comparable between RIF groups. However, CPR and LBR were significantly higher in group 3 (48.6% and 40.5%) than group 1 (36.4% and 27.9%), and group 2 (37.9% and 30.1%) (p = 0.007 and p = 0.005, respectively).

CONCLUSION

Unidentified endometrial factors except CE may also affect the implantation process, although CE is a frequent finding in patients with RIF. Reproductive outcomes may not be improved only with antibiotics in RIF patients with CE.

Approaches to Improve Endometrial Receptivity in Case of Repeated Implantation Failures

Repeated implantation failures are a constant challenge in reproductive medicine with a significant impact both on health providers and on infertile couples. Several approaches have been proposed so far as effective; however, accumulative data have clarified that most of the treatment options do not have the evidence base for a generalized application to be suggested by the relevant societies. Implantation failures are attributed to either poor quality embryos or to defected endometrial receptivity. The current review aims to summarize in a systematic way all the new trends in managing RIF via interference with endometrial receptivity. The authors focus mainly, but not exclusively, on endometrial injury prior to embryo transfer and endometrial priming with autologous cells or biological agents. To this direction, a systematic search of the Pubmed database has been conducted taking into account the emerged evidence of the last two decades. All the suggested interventions are herein presented and analyzed in terms of reproductive outcomes. It is evident that properly powered and designed randomized trials are needed to support a new standard approach in RIF treatment that will safely be incorporated in national and international guidelines.

The Effects of Acupuncture on Pregnancy Outcomes of Recurrent Implantation Failure: A Systematic Review and Meta-Analysis

Objective

To systematically evaluate the efficacy and safety of acupuncture for patients with recurrent implantation failure (RIF) undergoing in vitro fertilization-embryo transfer (IVF-ET) and hopefully provide reliable guidance for clinicians and patients.

Methods

Through searching domestic and foreign medical journals, the literature of randomized controlled trials (RCTs) of acupuncture for RIF undergoing IVF-ET was collected. RevMan 5.3 software was used for meta-analysis and Cochrane's risk of bias assessment tool was used to evaluate the quality of the included studies.

Results

Seven documents meeting the criteria were finally included. The results showed that the intervention group contributes more in outcomes including clinical pregnancy rate (RR = 1.90, 95% CI (1.51, 2.40), P < 0.05), biochemical pregnancy rate (RR = 1.59, 95% CI (1.27, 1.99), P < 0.05), embryo implantation rate (RR = 1.89, 95% CI (1.47, 2.45), P < 0.05), and endometrial thickness (MD = 1.11, 95% CI (0.59, 1.63), P < 0.05) when compared with the control group, and the difference is statistically significant. In terms of the number of embryo transfers and the type of endometrium, the difference between the acupuncture group and the control group was not statistically significant.

Conclusion

Acupuncture therapy on patients with RIF can improve the pregnancy outcome of patients. It is a relatively effective treatment with satisfactory safety and suitable for clinical application. However, as the quality of the included studies is not good enough, the conclusion of this meta-analysis should be treated with caution. More double-blind RCTs equipped with high quality and large samples are expected for the improvement of the level of evidence.

Efficacy of therapies and interventions for repeated embryo implantation failure: a systematic review and meta-analysis

The aim of the present systematic review and meta-analysis was to assess the effect of the different therapeutic options for repeated embryo implantation failure (RIF) on a subsequent IVF cycle outcome. Twenty-two RCTs and nineteen observational studies were included. Pooling of results showed a beneficial effect of intrauterine PBMC infusion on both CPR (RR 2.18; 95% CI 1.58-3.00; p < 0.00001; OR 2.03; 95% CI 1.22-3.36; p = 0.006) and LBR (RR 2.41; 95% CI 1.40-4.16; p = 0.002; OR 3.73; 95% CI 1.13-12.29; p = 0.03), of subcutaneous G-CSF administration on CPR (RR 2.29; 95% CI 1.58-3.31; p < 0.0001) and of intrauterine PRP infusion on CPR (RR 2.45; 95% CI 1.55-3.86; p = 0.0001). Observational studies also demonstrated a positive effect of IVIG and intrauterine hCG infusion on both CPR and LBR and of atosiban on CPR. Studies investigating intrauterine G-CSF infusion, LMWH, intravenous intralipid, hysteroscopy, blastocyst-stage ET, ZIFT, PGT-A and AH failed to observe an impact on IVF outcome. The quality of the evidence that emerged from RCTs focused on intrauterine PBMC infusion and subcutaneous G-CSF administration was moderate. For all other therapies/interventions it varied from low to very low. In conclusion, intrauterine PBMC infusion and subcutaneous G-CSF administration are the most promising therapeutic options for RIF. However, further well conducted RCTs are necessary before their introduction into clinical practice.

Determining Diagnostic Criteria of Unexplained Recurrent Implantation Failure: A Retrospective Study of Two vs Three or More Implantation Failure

BACKGROUND

The definition of recurrent implantation failure (RIF) differs clinically, one of the most controversial diagnostic criteria is the number of failed treatment cycles. We tried to investigate whether the two implantation failure could be included in the diagnostic criteria of RIF.

METHODS

A retrospective analysis of the clinical data of patients (N=1518) aged under 40 years with two or more implantation failure, recruited from the Center for Reproductive Medicine of the First Affiliated Hospital of Zhengzhou University from January 2016 to June 2019.

RESULTS

After adjusting for confounding factors by using binary logistic regression, the results showed that partial general information and: distribution of associated factors were significant differences such as maternal age (aOR=1.054, P=0.001), type of cycle (aOR=2.040, P<0.001), stage of embryos development (aOR=0.287, P<0.001), number of embryos transferred (aOR=0.184, P<0.001), female factor (tubal pathology) (aOR=0.432, P=0.031) and male factor (aOR=1.734, P=0.002) between the groups with two and three or more unexplained implantation failure. And further explored whether these differential factors had a significant negative impact on pregnancy outcome, the results showed that: for patients who had three unexplained implantation failure, in the fourth cycle of ET, the live birth rate decreased significantly with age (aOR=0.921, P<0.001), and the live birth rate of blastocyst transfer was significantly higher than that of cleavage embryo transfer (aOR=1.826, P=0.007). At their first assisted pregnancy treatment after the diagnosis of RIF according to these two different definitions, there were no significant difference in the biochemical pregnancy rate, clinical pregnancy rate, ectopic pregnancy rate and abortion rate (P>0.05), but the live birth rate (35.64% vs 42.95%, P=0.004) was significantly different. According to the definition of 'two or more failed treatment cycles', the live birth rate of the first ET treatment after RIF diagnosis was significantly lower than that of patients according to the definition of 'three or more failed treatment cycles'.

CONCLUSION

For patients with unexplained recurrent implantation failure, two implantation failure cannot be included in the diagnostic criteria of RIF. This study supports the generally accepted definition of three or more failed treatment cycles for RIF.

Prednisone improves pregnancy outcome in repeated implantation failure by enhance regulatory T cells bias

OBJECTIVE

Repeated implantation failure (RIF) has been shown related to maternal immune imbalance. Many studies suggested that prednisone promoted the Th17/Treg balance shift to the direction of immune tolerance. Our study aimed to evaluate the role of prednisone in Th17/Treg balance and pregnancy outcome in RIF patients.

STUDY DESIGN AND MAIN OUTCOME MEASURES

Peripheral blood of healthy fertile controls and RIF patients were collected at the late proliferation phase. The population of Treg and Th17 cells, the expression of Foxp3 and RORC mRNA and the concentration of IL-17A, IL-23 and IL-10 were detected by flow cytometry, qRT-PCR and enzyme-linked immunosorbent assay. RIF patients were given oral prednisone 10 mg daily from the late proliferation phase of the cycle before FET. After one month of treatment, the above immune indicators were tested, and natural cycle frozen embryo transfer was performed.

RESULTS

The Treg cells proportion and IL-10 concentration in peripheral blood of RIF patients was lower than that of NF group, while the proportion of Th17 cells and concentration of proinflammatory cytokine were significantly higher. After prednisone treatment, the indicators related to immune tolerance increased significantly. Five out of 19 RIF patients were successful pregnancy after FET, in which, one had an early miscarriage and four live births. No pregnancy complications and fetal abnormalities were observed.

CONCLUSIONS

We report the beneficial effect of prednisone on RIF patients. The underlying mechanism may attribute to shift the Treg/Th17 immune balance to a Treg bias, and enhance embryo implantation, ultimately improve pregnancy outcomes.