Effects of intrauterine perfusion of human chorionic gonadotropin in women with different implantation failure numbers

Meta-analysis of intrauterine hCG perfusion efficacy in recurrent implantation failure as defined by ESHRE guidelines

PURPOSE

This study evaluates the efficacy of intrauterine hCG perfusion for RIF, as defined by ESHRE 2023 guidelines, highlighting hCG as a cost-effective alternative to other immunotherapies, especially suitable for less developed regions. It aims to clarify treatment guidance amidst previous inconsistencies.

METHODS

This meta-analysis, registered with PROSPERO (CRD42024443241) and adhering to PRISMA guidelines, assessed the efficacy and safety of intrauterine hCG perfusion in enhancing implantation and pregnancy outcomes in RIF. Comprehensive literature searches were conducted through December 2023 in major databases including PubMed, Web of Science, Embase, the Cochrane Library, and key Chinese databases, without language restrictions. Inclusion and exclusion criteria were strictly aligned with the 2023 ESHRE recommendations, with exclusions for studies lacking robust control, clear outcomes, or adequate data integrity. The risk of bias was evaluated using the Newcastle-Ottawa Scale, ROBINS-I, and RoB2 tools. Data analysis was performed in R using the 'meta' package, employing both fixed and random effect models to account for study variability. Subgroup analyses by dosage, volume, hCG concentration, timing of administration, and type of embryo transfer were conducted to deepen insights, enhancing the reliability and depth of the meta-analysis in elucidating the role of hCG perfusion in RIF treatments.

RESULTS

Data from 13 studies, comprising six retrospective and six prospective studies from single centers, along with one multi-center RCT, totaling 2,157 participants, were synthesized to evaluate the effectiveness of intrauterine hCG perfusion in enhancing implantation and pregnancy outcomes in patients with RIF. Significant improvements were observed in clinical pregnancy and embryo implantation rates across various dosages, timing of administration, and embryo developmental stages, without impacting miscarriage rates. Notably, the most significant efficacy within subgroups occurred with a 500 IU dosage and perfusion parameters of ≤ 500µL volume and ≥ 2 IU/µL concentration. Additionally, a limited number of studies showed no significant increases in ectopic pregnancy or multiple pregnancy rates, and a modest improvement in live birth rates, although the small number of these studies precludes definitive conclusions.

CONCLUSIONS

The analysis suggests that intrauterine hCG perfusion probably enhances embryo implantation, clinical pregnancy, and live birth rates slightly in RIF patients. Benefits are indicated with a dosage of 500 IU and a maximum volume of 500µL at concentrations of at least 2 IU/µL. However, substantial heterogeneity from varying study types and the limited number of studies necessitate cautious interpretation. These findings underscore the need for more rigorously designed RCTs to definitively assess the efficacy and safety.

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.

Novel therapeutic options for treatment of recurrent implantation failure

Despite the challenges in studying recurrent implantation failure, progress is currently being made in therapeutic options to help those who suffer from recurrent implantation failure. Three of the most promising therapeutic options for recurrent implantation failure include immune therapies such as peripheral blood mononuclear cells, platelet rich plasma and subcutaneous granulocyte-colony stimulating factor.

Effects of human chorionic gonadotropin intrauterine injection on oocyte retrieval day on assisted reproductive techniques outcomes: An RCT

Background

Several mediators play an important role in implantation. One of these mediators is human chorionic gonadotropin (HCG).

Objective

To evaluate the effects of HCG intrauterine injection on the day of oocyte retrieval on the result of assisted reproductive techniques (ART).

Materials and Methods

In this randomized clinical trial study, 126 women who were referred to Afzalipour Infertility Center between December 2018 to December 2019 undergoing in vitro fertilization/intracytoplasmic sperm injection cycles were enrolled and assigned to two groups of: a case (n = 62) and a control group (n = 64). The protocols for both groups were the same; except that the case group was injected with the protocols for both groups were the same, except that the case group was injected with 1000 IU of HCG into uterine cavity following the oocyte puncture, while no medication was administered to the control group. The implantation rate, chemical pregnancy, clinical pregnancy, and abortion rates were compared between the two groups.

Results

Positive chemical pregnancy was seen in 15 (27.3%) cases of the case group and 14 (25.5%) of the control group. No significant difference was seen in the chemical and clinical pregnancy rates between the groups. The abortion rate was higher in the control group but that was not significant.

Conclusion

A 1000 IU of HCG intrauterine injection after oocyte retrieval does not improve implantation, chemical or clinical pregnancy rates in ART cycles. Further studies are needed to clearly understand the role of HCG intrauterine injection in the day of oocyte retrieval in ART outcomes.

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.

Human chorionic gonadotropin promotes recruitment of regulatory T cells in endometrium by inducing chemokine CCL2

Human chorionic gonadotropin (hCG) can attract regulatory T cells (Tregs) into the fetal-maternal interface regulating maternal immune tolerance in pregnancy. The objective of this study was to investigate whether hCG recruits the Tregs into endometrium by inducing chemokines. The number of Tregs in the endometrium was analyzed by immunohistochemistry. The expression of CCL2 was analyzed in vivo and in vitro with hCG stimulation. CD4+CD25+ Tregs were isolated from peripheral blood for Tregs migration assay with hCG, CCL2 siRNA and CCR2 antagonist stimulation. Our results showed that the number of endometrial Tregs in RIF patients was significantly decreased (9.4 ± 5.3 vs. 23.1 ± 3.1, P < 0.01), while intrauterine infusion of 2000 IU hCG increased the endometrial Tregs (18.6 ± 9.8 vs. 9.4 ± 5.3, P < 0.05) and CCL2 expression (0.21 ± 0.01 vs. 0.17 ± 0.01, P < 0.01). Horn injecting with 10 IU hCG also increased the endometrial Tregs in pseudopregnant mice (46 ± 16.8 vs. 7 ± 4.3, P < 0.01). Furthermore, the CCL2 protein and mRNA levels were significantly increased in human endometrial stromal cells (hESCs) with the stimulation of hCG. Migration assays showed that hESCs with hCG stimulation promoted Tregs migration (2597 ± 833.2 vs. 1115 ± 670.7, P < 0.05), while the number of migrated Tregs significantly decreased with CCL2 siRNA (1061 ± 105.4 vs. 2598 ± 294.7, P < 0.05) or CCR2 antagonist (356.7 ± 138.8 vs. 2597 ± 833.2, P < 0.05) treatment. In conclusion, intrauterine perfusion of hCG might promote the recruitment of Tregs into endometrium by inducing chemokine CCL2.

Human Chorionic Gonadotropin-Mediated Immune Responses That Facilitate Embryo Implantation and Placentation

Human chorionic gonadotropin (hCG) serves as one of the first signals provided by the embryo to the mother. Exactly at the time when the first step of the implantation process is initiated and the blastocyst adheres to the maternal endometrium, the embryonic tissue starts to actively secrete hCG. Shortly thereafter, the hormone can be detected in the maternal circulation where its concentration steadily increases throughout early pregnancy as it is continuously released by the forming placenta. Accumulating evidence underlines the critical function of hCG for embryo implantation and placentation. hCG not only regulates biological aspects of these early pregnancy events but also supports maternal immune cells in their function as helpers in the establishment of an adequate embryo-endometrial relationship. In view of its early presence in the maternal circulation, hCG has the potential to influence both local uterine immune cell populations as well as peripheral ones. The current review aims to summarize recent literature on the participation of innate and adaptive immune cells in embryo implantation and placentation with a specific focus on their regulation by hCG.

Effect of intrauterine perfusion of human chorionic gonadotropin before embryo transfer after two or more implantation failures: A systematic review and meta-analysis

OBJECTIVE

To investigate whether intrauterine perfusion of hCG before embryo transfer (ET) is effective in women experienced two or more implantation failures.

STUDY DESIGN

Systematic review and meta-analysis. In the current meta-analysis, Pubmed, EMBASE and The Cochrane Library were searched for trials which compared the efficacy of intrauterine perfusion of hCG with no perfusion of hCG in women undergoing in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI), or frozen embryo transfer (FET) before ET. The primary outcomes are the clinical pregnancy rate (CPR) and live birth rate (LBR).

RESULTS

Six trials consisted of 1432 women were eligible for quantitative analysis. CPR (including 6 trials consisted of 1432 women) and LBR (including 3 trials consisted of 870 women) were significantly improved in the hCG group compared to the control group, with a CPR of 41.8 % vs. 31.2 % (RR 1.30, 95 % CI 1.14∼1.50, P < .001), an LBR of 27.8 % vs. 18.0 % (RR 1.52, 95 % CI 1.18∼1.96, P = .001).

CONCLUSION

Intrauterine perfusion of hCG is effective in improving clinical pregnancy rate and live birth rate in women who experienced two or more implantation failures, which might provide a potential therapeutical intervention for recurrent implantation failure (RIF). Although promising, further evidence from multicenter, randomized controlled trials are needed to confirm the conclusion from the current meta-analysis.

Intrauterine infusion of human chorionic gonadotropin before embryo transfer in IVF/ET cycle: The critical review

Intrauterine infusion of human chorionic gonadotropin (IUI-hCG) has been proposed to improve the outcome of in vitro fertilization-embryo transfer (IVF-ET), since it plays a critical role in synchronizing endometrial and fetal development. As the early mediator from embryo, hCG promotes the decidualization, angiogenesis, maternal immune tolerance, and trophoblast invasion, favoring successful implantation of embryo. Although multiple clinical trials have been conducted to verify the efficacy of IUI-hCG on IVF-ET outcome in recent years, the findings remained controversial. The difference in study design and population might be the cause to the different consequences after administration of hCG. More importantly, the endometrial receptivity, which might affect the efficacy of IUI-hCG, has not been assessed in women receiving this intervention. Selecting the right population suitable for IUI-hCG based on known etiology would be crucial in enhancing its efficacy and minimize any possible complications. Investigation of optimal indications for IUI-hCG should be highlighted in the future.

Intrauterine administration of human chorionic gonadotropin (hCG) for subfertile women undergoing assisted reproduction

BACKGROUND

Most women undergoing assisted reproduction treatment will reach the stage of embryo transfer (ET), but the proportion of embryos that can be successfully implanted after ET has remained small since the mid-1990s. Human chorionic gonadotropin (hCG) is a hormone that is synthesised and released by the syncytiotrophoblast and has a fundamental role in embryo implantation and the early stages of pregnancy. Intrauterine administration of hCG via ET catheter during a mock procedure around the time of ET is a novel approach that has been suggested to improve the outcomes of assisted reproduction.

OBJECTIVES

To investigate whether intrauterine (intracavity) administration of hCG (IC-hCG) around the time of ET improves clinical outcomes in subfertile women undergoing assisted reproduction.

SEARCH METHODS

We performed searches on 9 January 2018 using Cochrane methods.

SELECTION CRITERIA

We looked for randomised controlled trials (RCTs) evaluating IC-hCG around the time of ET, irrespective of language and country of origin.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed risk of bias, extracted data from studies, and attempted to contact study authors when data were missing. We performed statistical analysis using Review Manager 5. We assessed evidence quality using GRADE methods. Primary outcomes were live birth and miscarriage; secondary outcomes were clinical pregnancy rate and complications.

MAIN RESULTS

Seventeen RCTs investigated the effects of IC-hCG administration for 4751 subfertile women undergoing assisted reproduction. IC-hCG was administered in variable doses at different times before the ET. hCG was obtained from the urine of pregnant women or from cell cultures using recombinant DNA technology.Most studies (12/17) were at high risk of bias in at least one of the seven domains assessed. Common problems were unclear reporting of study methods and lack of blinding. The main limitations for evidence quality were high risk of bias and serious imprecision.For analyses of live birth and clinical pregnancy, there was considerable heterogeneity (I² > 75%) and therefore we present subgroups for dosage and stage of ET. Exploration for sources of heterogeneity revealed two key prespecified variables as important determinants: stage of ET (cleavage vs blastocyst stage) and dose of IC-hCG (< 500 international units (IU) vs ≥ 500 IU). We performed meta-analyses within subgroups defined by stage of embryo and dose of IC-hCG.Live birth rates among women having cleavage-stage ET with an IC-hCG dose < 500 IU compared to women having cleavage-stage ET without IC-hCG showed no benefit of the intervention and would be consistent with no substantive difference or disadvantage of indeterminate magnitude (risk ratio (RR) 0.76, 95% confidence interval (CI) 0.58 to 1.01; one RCT; 280 participants; I² = 0%; very low-quality evidence). In a clinic with a live birth rate of 49% per cycle, use of IC-hCG < 500 IU would be associated with a live birth rate ranging from 28% to 50%.Results show an increase in live birth rate in the subgroup of women undergoing cleavage-stage ET with an IC-hCG dose ≥ 500 IU compared to women having cleavage-stage ET without IC-hCG (RR 1.57, 95% CI 1.32 to 1.87; three RCTs; 914 participants; I² = 0%; moderate-quality evidence). At a clinic with a live birth rate of 27% per cycle, use of IC-hCG ≥ 500 IU would be associated with a live birth rate ranging from 36% to 51%.Results show no substantive differences in live birth among women having blastocyst-stage ET with an IC-hCG dose ≥ 500 IU compared to women having blastocyst-stage ET without IC-hCG (RR 0.92, 95% CI 0.80 to 1.04; two RCTs; 1666 participants; I² = 0%; moderate-quality evidence). At a clinic with a live birth rate of 36% per cycle, use of IC-hCG ≥ 500 IU would be associated with a live birth rate ranging from 29% to 38%.Evidence for clinical pregnancy among women having cleavage-stage ET with an IC-hCG dose < 500 IU showed no benefit of the intervention and would be consistent with no substantive difference or disadvantage of indeterminate magnitude (RR 0.88, 95% CI 0.70 to 1.10; one RCT; 280 participants; I² = 0%; very low-quality evidence).Results show an increase in clinical pregnancy rate in the subgroup of women having cleavage-stage ET with an IC-hCG dose ≥ 500 IU compared to women having cleavage-stage ET without IC-hCG (RR 1.49, 95% CI 1.32 to 1.68; 12 RCTs; 2186 participants; I² = 18%; moderate-quality evidence).Results show no substantive differences in clinical pregnancy among women having blastocyst-stage ET with an IC-hCG dose ≥ 500 IU (RR 0.99, 95% CI 0.85 to 1.15; four RCTs; 2091 participants; I² = 42%; moderate-quality evidence) compared to women having blastocyst-stage ET with no IC-hCG.No RCTs investigated blastocyst-stage ET with an IC-hCG dose < 500 IU.We are uncertain whether miscarriage was influenced by intrauterine hCG administration (RR 1.04, 95% CI 0.81 to 1.35; 11 RCTs; 3927 participants; I² = 0%; very low-quality evidence).Reported complications were ectopic pregnancy (four RCTs; 1073 participants; four events overall), heterotopic pregnancy (one RCT; 495 participants; one event), intrauterine death (three RCTs; 1078 participants; 22 events), and triplets (one RCT; 48 participants; three events). Events were few, and very low-quality evidence was insufficient to permit conclusions to be drawn.

AUTHORS' CONCLUSIONS

There is moderate quality evidence that women undergoing cleavage-stage transfer using an IC-hCG dose ≥ 500 IU have an improved live birth rate. There is insufficient evidence for IC-hCG treatment for blastocyst transfer. There should be further trials with live birth as the primary outcome to identify the groups of women who would benefit the most from this intervention. There was no evidence that miscarriage was reduced following IC-hCG administration, irrespective of embryo stage at transfer or dose of IC-hCG. Events were too few to allow conclusions to be drawn with regard to other complications.