Chronic endometritis due to common bacteria is prevalent in women with recurrent miscarriage as confirmed by improved pregnancy outcome after antibiotic treatment

Engineered exosome as a biological nanoplatform for drug delivery of Rosmarinic acid to improve implantation in mice with induced endometritis

Endometritis is an inflammatory and histopathologic disease in uterine tissues that interferes with the proper decidualization and implantation of the embryo. In this study, rosmarinic acid (RA) is used as an anti-inflammatory agent that encapsulates in exosomes and is used to attenuate lipopolysaccharide (LPS)-induced endometritis and improve implantation. For this purpose, exosomes were loaded with RA and then administrated into the animal groups, including RA, exosome, RA plus exosome (RA + Exo), and RA-loaded exosomes (RALExo) groups. The concentrations of RA or exosomes used in this study were 10 mg/kg, and the compounds were injected into the uterine horn 24 h following the induction of endometritis. Upon the presence of inflammation detected by the histopathological method, the most proper groups were mated with male mice. The effect of the treatment group on the implantation rate, progesterone levels, and gene expressions were assessed by Chicago Blue staining, enzyme-linked immunosorbent assay (ELISA), and Quantitative PCR (qPCR), respectively. Results showed RALExo10 and RA10 + Exo10 groups improved pathological alterations, enhanced progesterone levels, increased implantation rate, as well as heightened expression levels of Leukemia inhibitory factor (LIF) and Mucin-16 (MUC-16) genes. Besides, the expression levels of inflammatory cytokines, including Transforming growth factor-β (TGF-β), Interlukine-10 (IL-10), Interlukine-15 (IL-15), and Interlukine-18 (IL-18), were regulated. Our findings indicated that the expression of LIF, Muc-16 genes as well as IL-18, were significantly correlated with serum progesterone concentrations and the implantation rate in the treatment groups. The RALExo10 and RA10 + Exo10 groups showed ameliorated implantation rates in experimental groups.

Recombinant humanized type I collagen remodels decidual immune microenvironment at maternal-fetal interface by modulating Th17/Treg imbalance

Disruption of the extracellular matrix and dysregulation of the balance between Th17 and regulatory T cells are recognized as risk factors for recurrent spontaneous abortion (RSA). However, the interaction between matrix components and the Th17/Treg axis remains poorly elucidated. The result of this study revealed that the absence of type I collagen in the decidua is linked to Th17/Treg imbalance in RSA. Furthermore, we discovered that biomaterial recombinant humanized type I collagen (rhCOLI) promoted T cell differentiation into Tregs by inhibition the Notch1/Hes1 signaling pathway and enhanced the immunosuppressive function of Tregs, as indicated by increased secretion level of IL-10 and TGF-β. Importantly, this study is the first to demonstrate that rhCOLI can modulate the Th17/Treg imbalance, reduce embryo resorption rates, reshape the immune microenvironment at the maternal-fetal interface, and improve fertility in an RSA mouse model. Collectively, these findings suggest that type I collagen deficiency may contribute to, rather than result from, RSA, and propose a potential intervention for RSA using rhCOLI.

Australasian recurrent pregnancy loss clinical management guideline 2024, part II

Part II of the Australasian guideline for the investigation and management of recurrent pregnancy loss (RPL) provides evidence-based guidance on the management of RPL provided. The implications of inherited and acquired thrombophilia with respect to RPL and suggestions for clinical management are provided. Autoimmune factors, including human leukocyte antigen, cytokines, antinuclear antibodies and coeliac antibodies, and guidance for management are discussed. Infective, inflammatory and endometrial causes of RPL are discussed in detail. Environmental and lifestyle factors, male factor and unexplained causes are outlined. Levels of evidence and grades of consensus are provided for all evidence-based statements.

Chronic endometritis and the endometrial microbiota: implications for reproductive success in patients with recurrent implantation failure

BACKGROUND

Chronic endometritis (CE) is associated with poor reproductive outcomes, yet the role of endometrial microbiota in patients with recurrent implantation failure (RIF) and CE remains unclear. This study aims to characterize endometrial microbiota in RIF patients with CE and assess its implications for reproductive outcomes.

METHODS

In this prospective study, we enrolled RIF patients both with and without CE. Endometrial and cervical samples were collected for 16 S rRNA gene sequencing. Microbiota composition was compared between groups using diversity indices, phylum, and genus-level analysis. Canonical correlation analysis (CCA) and Spearman's correlation coefficients were used to assess relationships between CE, reproductive outcomes, and microbiota. Predictive functional profiling was performed to evaluate metabolic pathways associated with CE.

RESULTS

Endometrial microbiota in CE patients exhibited greater diversity and evenness compared to non-CE patients. Principal coordinates analysis (PCoA) revealed distinct clustering between CE and non-CE groups. Linear discriminant analysis (LDA) identified Proteobacteria, Aminicenantales, and Chloroflexaceae as characteristic of CE, while Lactobacillus, Acinetobacter, Herbaspirillum, Ralstonia, Shewanela, and Micrococcaceae were associated with non-CE. CCA demonstrated associations between CE, adverse reproductive outcomes, and specific bacterial taxa. Microbial metabolic pathways significantly differed between CE and non-CE groups, with enrichment in pathways related to cofactors, vitamins, secondary metabolites, and the immune system in CE patients.

CONCLUSION

RIF patients with CE exhibit distinct endometrial microbiota compositions associated with adverse reproductive outcomes. The increased microbial diversity and altered metabolic pathways in CE suggest a potential correlation with reproductive outcomes, although further studies are necessary to elucidate the causal relationship between microbiota alterations and fertility. Modulating the endometrial microbiome may represent a novel therapeutic strategy to improve IVF outcomes in patients with CE.

Correlation between hysteroscopic features and specific microbial species in women with chronic endometritis

Objective and rationale

Chronic endometritis (CE) has recently been associated with unexplained infertility and recurrent miscarriages. The current gold standard for CE detection is histopathological examination. However, office hysteroscopy and endometrial cultures are also significant, due to the possible link between CE and various microorganisms. Bacterial colonization of the endometrium has been associated with reduced success rates of in vitro fertilisation embryo transfer. Few studies have tried to correlate CE hysteroscopy findings with pathogenic microorganisms. This prospective cohort study sought to establish whether hysteroscopic diagnostic lesions correlate with specific microbial species.

Methods

The study encompassed women undergoing diagnostic tests for a range of subfertility health issues. 189 women completed the standard office diagnostic hysteroscopy (DH). 181 had also endometrial samples taken for microbial culture investigation. Correlation analysis (χ2 and Fisher's exact test) between hysteroscopic findings suggestive of CE and endometrial cultures was carried out. Logistic regression models were also fitted to measure whether a positive endometrial culture could affect CE conditions.

Results

A significant association of E. coli was observed between the hysteroscopically characterized CE + group with focal hyperplasia, when compared to the non-CE group. Logistic regression analysis revealed that women positive for E. coli were 4.423 times more likely to have focal endometrial hyperplasia. No other significant correlations were identified between DH and positive endometrial cultures.

Conclusions

The presence of E. coli in the endometrium was significantly correlated with focal hyperplasia findings from hysteroscopy, emphasizing the importance of microbial cultures in the diagnosis and targeted treatment of CE in women with subfertility.

Bacterial infection in endometriosis: a silver-lining for the development of new non-hormonal therapy?

The pathogenesis of endometriosis is a hotly debated topic, yet still cloaked in multiple layers of hypothetical theories. A recent report raises the possibility that bacterial infection, especially those of the genus Fusobacterium, may be the cause of endometriosis, at least in certain women. More importantly, the demonstration that treatment with broad-spectrum antibiotics significantly reduced the size of lesions in a mouse endometriosis model rekindles the hope for new non-hormonal treatments. The development of new therapies has been plagued by strings of unsuccessful clinical trials over the last two decades. Is this antibiotic therapy, a silver lining for the research and development of non-hormonal drugs for endometriosis?

The endometrial microbiota and early pregnancy loss

The human endometrium is a dynamic entity that plays a pivotal role in mediating the complex interplay between the mother and developing embryo. Endometrial disruption can lead to pregnancy loss, impacting both maternal physical and psychological health. Recent research suggests that the endometrial microbiota may play a role in this, although the exact mechanisms are still being explored, aided by recent technological advancements and our growing understanding of host immune responses. Suboptimal or dysbiotic vaginal microbiota, characterized by increased microbial diversity and reduced Lactobacillus dominance, has been associated with various adverse reproductive events, including miscarriage. However, the mechanisms linking the lower reproductive tract microbiota with pregnancy loss remain unclear. Recent observational studies implicate a potential microbial continuum between the vaginal and endometrial niche in patients with pregnancy loss; however, transcervical sampling of the low biomass endometrium is highly prone to cross-contamination, which is often not controlled for. In this review, we explore emerging evidence supporting the theory that a dysbiotic endometrial microbiota may modulate key inflammatory pathways required for successful embryo implantation and pregnancy development. We also highlight that a greater understanding of the endometrial microbiota, its relationship with the local endometrial microenvironment, and potential interventions remain a focus for future research.

The reproductive microbiome in dogs: Friend or foe?

The microbiome of the reproductive tract is an area of research in full development. Specifically, the microbiome may be involved in reproductive health, disease, and pregnancy outcomes, as has been shown in humans and animals, including dogs. The aim of the present review was to summarize current knowledge on the microbiome of the canine reproductive tract, to expose the controversial role that some bacterial agents may play in canine subfertility, and to highlight future research perspectives. This review discussed whether the use of antimicrobials in dogs is appropriate to increase reproductive performance and to treat subfertility without proper diagnosis, and the possible use of probiotics to modulate the reproductive canine microbiome. Finally, we indicate areas in which scientific knowledge is currently lacking, and could be promising directions for future research.

The role of the endometrial microbiome in embryo implantation and recurrent implantation failure

There is a suggested pathophysiology associated with endometrial microbiota in cases where repeated implantation failure of high-quality embryos is observed. However, there is a suspected association between endometrial microbiota and the pathogenesis of implantation failure. However, there is still a lack of agreement on the fundamental composition of the physiological microbiome within the uterine cavity. This is primarily due to various limitations in the studies conducted, including small sample sizes and variations in experimental designs. As a result, the impact of bacterial communities in the endometrium on human reproduction is still a subject of debate. In this discourse, we undertake a comprehensive examination of the existing body of research pertaining to the uterine microbiota and its intricate interplay with the process of embryo implantation.

Bacteriophages, gut bacteria, and microbial pathways interplay in cardiometabolic health

Cardiometabolic diseases are leading causes of mortality in Western countries. Well-established risk factors include host genetics, lifestyle, diet, and the gut microbiome. Moreover, gut bacterial communities and their activities can be altered by bacteriophages (also known simply as phages), bacteria-infecting viruses, making these biological entities key regulators of human cardiometabolic health. The manipulation of bacterial populations by phages enables the possibility of using phages in the treatment of cardiometabolic diseases through phage therapy and fecal viral transplants. First, however, a deeper understanding of the role of the phageome in cardiometabolic diseases is required. In this review, we first introduce the phageome as a component of the gut microbiome and discuss fecal viral transplants and phage therapy in relation to cardiometabolic diseases. We then summarize the current state of phageome research in cardiometabolic diseases and propose how the phageome might indirectly influence cardiometabolic health through gut bacteria and their metabolites.

The Clinical Application of Platelet-Rich Plasma in the Female Reproductive System: A Narrative Review

Platelet-rich plasma is an autologous plasma containing platelets prepared from fresh whole blood drawn from a peripheral vein. Through processing, it can be prepared to contain supraphysiologic levels of platelets at three to five times greater than the level of normal plasma. PRP has been explored both in vivo and ex vivo in the human endometrium model in its ability to harness the intrinsic regenerative capacity of the endometrium. Intrauterine autologous PRP infusions have been shown to increase endometrial thickness and reduce the rate of intrauterine adhesions. In the setting of recurrent implantation failure, intrauterine infusion of PRP has been shown to increase clinical pregnancy rate. PRP also appears to hold a potential role in select patients with premature ovarian insufficiency, poor ovarian responders and in improving outcomes following frozen-thawed transplantation of autologous ovarian tissue. Further studies are required to explore the potential role of PRP in reproductive medicine further, to help standardise PRP protocols and evaluate which routes of administration are most effective.

Preconceptual administration of doxycycline in women with recurrent miscarriage and chronic endometritis: protocol for the Chronic Endometritis and Recurrent Miscarriage (CERM) trial, a multicentre, double-blind, placebo-controlled, adaptive randomised trial with an embedded translational substudy

INTRODUCTION

Recurrent miscarriage is a common condition with a substantial associated morbidity. A hypothesised cause of recurrent miscarriage is chronic endometritis (CE). The aetiology of CE remains uncertain. An association between CE and recurrent miscarriage has been shown. This study will aim to determine if preconceptual administration of doxycycline, in women with recurrent miscarriages, and CE, reduces first trimester miscarriages, increasing live births.

METHODS AND ANALYSIS

Chronic Endometritis and Recurrent Miscarriage is a multicentre, double-blind adaptive trial with an embedded translational substudy. Women with a history of two or more consecutive first trimester losses with evidence of CE on endometrial biopsy (defined as ≥5 CD138 positive cells per 10 mm2) will be randomised to oral doxycycline or placebo for 14 days. A subset will be recruited to a mechanistic substudy in which microbial swabs and preintervention/postintervention endometrial samples will be collected. Up to 3062 women recruited from 29 National Health Service (NHS) hospital sites across the UK are expected to be screened with up to 1500 women randomised in a 1:1 ratio. Women with a negative endometrial biopsy (defined as <5 CD138 positive cells per 10 mm2) will also be followed up to test validity of the tool. The primary outcome is live births plus pregnancies ≥24 + 0 weeks gestation at the end of the trial, in the first or subsequent pregnancy. Secondary clinical outcomes will also be assessed. Exploratory outcomes will assess the effect of doxycycline treatment on the endometrial microbiota, the differentiation capacity of the endometrium and the senescent profile of the endometrium with CE.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the NHS Research Ethics Committee Northwest-Haydock (19/NW/0462). Written informed consent will be gained from all participants. The results will be published in an open-access peer-reviewed journal and reported in the National Institute for Health and Care Research journals library.

TRIAL REGISTRATION NUMBER

ISRCTN23947730.

Recurrent MiscarriageGreen-top Guideline No. 17

In this guideline, recurrent miscarriage has been defined as three or more first trimester miscarriages. However, clinicians are encouraged to use their clinical discretion to recommend extensive evaluation after two first trimester miscarriages, if there is a suspicion that the miscarriages are of pathological and not of sporadic nature. Women with recurrent miscarriage should be offered testing for acquired thrombophilia, particularly for lupus anticoagulant and anticardiolipin antibodies, prior to pregnancy. [Grade C] Women with second trimester miscarriage may be offered testing for Factor V Leiden, prothrombin gene mutation and protein S deficiency, ideally within a research context. [Grade C] Inherited thrombophilias have a weak association with recurrent miscarriage. Routine testing for protein C, antithrombin deficiency and methylenetetrahydrofolate reductase mutation is not recommended. [Grade C] Cytogenetic analysis should be offered on pregnancy tissue of the third and subsequent miscarriage(s) and in any second trimester miscarriage. [Grade D] Parental peripheral blood karyotyping should be offered for couples in whom testing of pregnancy tissue reports an unbalanced structural chromosomal abnormality [Grade D] or there is unsuccessful or no pregnancy tissue available for testing. [GPP] Women with recurrent miscarriage should be offered assessment for congenital uterine anomalies, ideally with 3D ultrasound. [Grade B] Women with recurrent miscarriage should be offered thyroid function tests and assessment for thyroid peroxidase (TPO) antibodies. [Grade C] Women with recurrent miscarriage should not be routinely offered immunological screening (such as HLA, cytokine and natural killer cell tests), infection screening or sperm DNA testing outside a research context. [Grade C] Women with recurrent miscarriage should be advised to maintain a BMI between 19 and 25 kg/m2 , smoking cessation, limit alcohol consumption and limit caffeine to less than 200 mg/day. [Grade D] For women diagnosed with antiphospholipid syndrome, aspirin and heparin should be offered from a positive test until at least 34 weeks of gestation, following discussion of potential benefits versus risks. [Grade B] Aspirin and/or heparin should not be given to women with unexplained recurrent miscarriage. [Grade B] There are currently insufficient data to support the routine use of PGT-A for couples with unexplained recurrent miscarriage, while the treatment may carry a significant cost and potential risk. [Grade C] Resection of a uterine septum should be considered for women with recurrent first or second trimester miscarriage, ideally within an appropriate audit or research context. [Grade C] Thyroxine supplementation is not routinely recommended for euthyroid women with TPO who have a history of miscarriage. [Grade A] Progestogen supplementation should be considered in women with recurrent miscarriage who present with bleeding in early pregnancy (for example 400 mg micronised vaginal progesterone twice daily at the time of bleeding until 16 weeks of gestation). [Grade B] Women with unexplained recurrent miscarriage should be offered supportive care, ideally in the setting of a dedicated recurrent miscarriage clinic. [Grade C].

Impact of a previous late miscarriage on subsequent pregnancy outcomes: A retrospective cohort study over 10 years

OBJECTIVE

To explore the prognostic impact of a previous late miscarriage (LM) on the subsequent pregnancy outcomes of women with infertility.

METHOD

This retrospective cohort study included couples who had experienced LM following their first embryo transfer during an in vitro fertilization (IVF) cycle from January 2008 to December 2020. Subgroup analysis and binary logistic regression were performed to evaluate the associations between LM due to different causes and subsequent pregnancy outcomes.

RESULTS

A total of 1072 women who had experienced LM were included in this study, comprising 458, 146, 412, and 56 women with LM due to unexplained factors (unLM), fetal factors (feLM), cervical factors (ceLM; i.e. cervical incompetence), and trauma factors (trLM), respectively. Compared with the general IVF (gIVF) population, the early miscarriage rate was significantly higher in the unLM group (8.28% vs. 13.47%, adjusted odds ratio [OR] 1.60, 95% confidence interval [95% CI] 1.12-2.28; P = 0.01). Furthermore, women in the unLM and ceLM groups had a dramatically increased risk of recurrent LM (unLM: 4.24% vs. 9.43%, aOR 1.91, 95% CI 1.24-2.94; P = 0.003; ceLM: 4.24% vs.15.53%, aOR 2.68, 95% CI 1.82-3.95; P < 0.001) and consequently a reduced frequency of live birth (unLM: 49.96% vs. 43.01%, aOR 0.75, 95% CI 0.61-0.91; P = 0.004; ceLM: 49.96% vs. 38.59%, aOR 0.61, 95% CI 0.49-0.77; P < 0.001) compared with the gIVF population.

CONCLUSION

A previous LM due to an unexplained factor or cervical incompetence was significantly associated with a higher risk of miscarriage and a lower live birth rate after subsequent embryo transfer.

Endometrial responses to bacterial and viral infection: a scoping review

BACKGROUND

The endometrium is a highly dynamic tissue that undergoes dramatic proliferation and differentiation monthly in order to prepare the uterus for implantation and pregnancy. Intrauterine infection and inflammation are being increasingly recognized as potential causes of implantation failure and miscarriage, as well as obstetric complications later in gestation. However, the mechanisms by which the cells of the endometrium respond to infection remain understudied and recent progress is slowed in part owing to similar overlapping studies being performed in different species.

OBJECTIVE AND RATIONALE

The aim of this scoping review is to systematically summarize all published studies in humans and laboratory animals that have investigated the innate immune sensing and response of the endometrium to bacteria and viruses, and the signaling mechanisms involved. This will enable gaps in our knowledge to be identified to inform future studies.

SEARCH METHODS

The Cochrane Library, Ovid Embase/Medline, PubMed, Scopus, Google Scholar, and Web of Science databases were searched using a combination of controlled and free text terms for uterus/endometrium, infections, and fertility to March 2022. All primary research papers that have reported on endometrial responses to bacterial and viral infections in the context of reproduction were included. To focus the scope of the current review, studies in domesticated animals, included bovine, porcine, caprine, feline, and canine species were excluded.

OUTCOMES

This search identified 42 728 studies for screening and 766 full-text studies were assessed for eligibility. Data was extracted from 76 studies. The majority of studies focused on endometrial responses to Escherichia coli and Chlamydia trachomatis, with some studies of Neisseria gonorrhea, Staphylococcus aureus, and the Streptococcus family. Endometrial responses have only been studied in response to three groups of viruses thus far: HIV, Zika virus, and the herpesvirus family. For most infections, both cellular and animal models have been utilized in vitro and in vivo, focusing on endometrial production of cytokines, chemokines, and antiviral/antimicrobial factors, and the expression of innate immune signaling pathway mediators after infection. This review has identified gaps for future research in the field as well as highlighted some recent developments in organoid systems and immune cell co-cultures that offer new avenues for studying endometrial responses to infection in more physiologically relevant models that could accelerate future findings in this area.

WIDER IMPLICATIONS

This scoping review provides an overarching summary and benchmark of the current state of research on endometrial innate immune responses to bacterial and viral infection. This review also highlights some exciting recent developments that enable future studies to be designed to deepen our understanding of the mechanisms utilized by the endometrium to respond to infection and their downstream effects on uterine function.

Decidualization dampens toll-like receptor mediated inflammatory responses in human endometrial stromal cells by upregulating IκBα

Endometrial stromal cells (EnSCs) are the major cell type of the human endometrium and they undergo dramatic differentiation, termed decidualization, every month that enables them to be receptive to implantation. Appropriate decidualization and EnSC function is key for a successful pregnancy. EnSC function may be affected when the uterus is exposed to bacterial and viral infection. However, how human EnSCs respond to viral and bacterial components have not been well-studied and it remains unclear whether uterine innate immune responses change during decidualization. This study demonstrated that viral double-stranded RNA [Poly(I:C)] and bacterial lipopolysaccharide (LPS) upregulated undecidualized human EnSC production of a large array of proinflammatory cytokines and chemokines, and revealed that these immune responses were significantly dampened during decidualization in vitro and in vivo. This dampened response was associated with increased NFKBIA transcription during decidualization that leads to the accumulation of this negative regulator in decidualizing EnSCs that can bind to NFκB p65 and prevents its nuclear translocation and downstream Toll-like receptor signaling. These findings highlight that endometrial responses to infection may vary at different stages of the menstrual cycle which may be important for preparing the endometrium to support the growth of the semi-allogenic blastocyst. This work emphasizes the need to consider menstrual cycle stage, sex hormone levels and the differentiation status of cells when examining inflammatory responses in the future.

Uterine Microbiome: Does the Sampling Technique Matter?

Studies have proven the significance of microbial communities in various parts of the human body for health. In recent years it has been discovered that the uterine cavity is not sterile, and endometrium has its own microbiome which appears to have an impact on female fertility and gynecological pathologies. Lactobacillus has shown to dominate the microbial profile in the uterus and is considered an indicator of a healthy uterine environment. Yet, many argue that the Lactobacillus dominance is due to vaginal contamination during the sampling process. To date there is no clearly defined healthy endometrial microbial profile, which is largely due to the fact that determining the microbial community from the endometrium is complicated, and there is currently no consensus on sampling methods for the endometrial microbiome. As a result, this restricts ability to replicate discoveries made in other cohorts. Here we aim to give an overview of the sampling methods used and discuss what impedes the endometrial microbiome studies as well as how to reach a consensus on the study design. This knowledge could be incorporated into the future research and the knowledge on endometrial microbiome could be included into the diagnostics and treatment of female reproductive health.

The Endometrial Microbiota: Challenges and Prospects

Contrary to popular belief, we have known for many years that the endometrium is not a sterile environment and is considered to be a low-biomass milieu compared to the vagina. Numerous trials and studies have attempted to establish a valid sampling method and assess its physiological composition, but no consensus has been reached. Many factors, such as ethnicity, age and inflammation, can influence the microbiome. Moreover, it possesses a higher alpha-diversity and, therefore, contains more diverse bacteria than the vagina. For instance, Lactobacillus has been shown to be a predominant genus in the vaginal microbiome of healthy women. Consequently, even if a majority of scientists postulate that a predominance of Lactobacillus inside the uterus improves reproductive outcomes, vaginal contamination by these bacteria during sampling cannot be ruled out. Certain pathologies, such as chronic endometritis, have been identified as inflammation perpetrators that hinder the embryo implantation process. This pro-inflammatory climate created by dysbiosis of the endometrial microbiota could induce secondary inflammatory mediators via Toll-like receptors, creating an environment conducive to the development of endometriosis and even promoting carcinogenesis. However, studies to this day have focused on small populations. In addition, there is no clearly defined healthy uterine composition yet. At most, only a few taxa have been identified as pathogenic. As sampling and analysis methods become increasingly precise, we can expect the endometrial microbiota to be incorporated into future diagnostic tools and treatments for women's health.

Immune Checkpoints in Recurrent Pregnancy Loss: New Insights into a Detrimental and Elusive Disorder

Recurrent pregnancy loss (RPL) refers to two or more miscarriages before 20 weeks gestation. Its prevalence is 1-2%; its pathogenesis remains unexplained in more than 50% of cases, in which the cause is thought to be abnormal immune activity during placentation leading to a lack of pregnancy-induced immune tolerance. It is unknown whether immune activity is deranged in the endometrium of women with RPL. We studied the gene expression and the quantitative tissue protein levels of three immune checkpoints (CD276, which enhances cytotoxic T-cell activity, cytotoxic T-lymphocyte-associated antigen-4 [CTL-4], which reduces Th1 cytokine production, and lymphocyte activation gene-3 [LAG-3], which shows suppressive activity on Tregs and CD4+ T-cells) in endometrial samples from 27 women with unexplained RPL and in 29 women with dysfunctional uterine bleeding and previous uneventful pregnancies as controls. RNA isolation, real-time PCR, protein isolation, and ELISA were performed. CD276 gene expression and protein tissue levels were significantly lower in the endometrium of the RPL group than in the controls, whereas both CTL-4 and LAG-3 were significantly higher. This difference suggests defective endometrial immune regulation and overactivation of immune response in women with a history of RPL, at least in relation to controls with dysfunctional uterine bleeding and previous normal reproductive history.

The Role of Plasma Cells as a Marker of Chronic Endometritis: A Systematic Review and Meta-Analysis

Chronic endometritis (CE) is the persistent inflammation of the endometrial lining associated with infertility and various forms of reproductive failures. The diagnosis of CE is based on the histological evidence of stromal plasma cells; however, standardized methods to assess plasma cells are still lacking. In the present paper, we aimed to determine the most appropriate plasma cell threshold to diagnose CE based on pregnancy outcomes. Three electronic databases were searched from their inception to February 2022 for all studies comparing pregnancy outcomes between patients with CE and patients without CE. The relative risk (RR) of pregnancy, miscarriage, and/or live birth rates were calculated and pooled based on the plasma cell threshold adopted. A p-value < 0.05 was considered significant. Nine studies adopting different thresholds (1 to 50 plasma cells/10 HPF) were included. In the meta-analysis, we only found a significant association between miscarriage rate and a plasma cell count ≥ 5/10 HPF (RR = 2.4; p = 0.007). Among studies not suitable for meta-analysis, CE showed an association with worsened pregnancy only when high thresholds (10 and 50/10 HPF) were adopted. In conclusion, our study suggests that the presence of plasma cells at low levels (<5/10 HPF) may not predict worsened pregnancy outcomes. Based on these findings, a threshold of ≥5 plasma cells/10 HPF may be more appropriate to diagnose CE.

Investigation and Management of Recurrent Pregnancy Loss: A Comprehensive Review of Guidelines

Importance

Recurrent pregnancy loss (RPL) is one of the most frustrating clinical entities in reproductive medicine requiring not only diagnostic investigation and therapeutic intervention, but also evaluation of the risk for recurrence.

Objective

The aim of this study was to review and compare the most recently published major guidelines on investigation and management of RPL.

Evidence Acquisition

A descriptive review of guidelines from the Royal College of Obstetricians and Gynaecologists, the European Society of Human Reproduction and Embryology, the American Society for Reproductive Medicine, the French College of Gynecologists and Obstetricians, and the German, Austrian, and Swiss Society of Gynecology and Obstetrics on RPL was carried out.

Results

There is consensus among the reviewed guidelines that the mainstays of RPL investigation are a detailed personal history and screening for antiphospholipid syndrome and anatomical abnormalities of the uterus. In contrast, inherited thrombophilias, vaginal infections, and immunological and male factors of infertility are not recommended as part of a routine RPL investigation. Several differences exist regarding the necessity of the cytogenetic analysis of the products of conception, parental peripheral blood karyotyping, ovarian reserve testing, screening for thyroid disorders, diabetes or hyperhomocysteinemia, measurement of prolactin levels, and performing endometrial biopsy. Regarding the management of RPL, low-dose aspirin plus heparin is indicated for the treatment of antiphospholipid syndrome and levothyroxine for overt hypothyroidism. Genetic counseling is required in case of abnormal parental karyotype. The Royal College of Obstetricians and Gynaecologists, the European Society of Human Reproduction and Embryology, and the French College of Gynecologists and Obstetricians guidelines provide recommendations that are similar on the management of cervical insufficiency based on the previous reproductive history. However, there is no common pathway regarding the management of subclinical hypothyroidism and the surgical repair of congenital and acquired uterine anomalies. Use of heparin for inherited thrombophilias and immunotherapy and anticoagulants for unexplained RPL are not recommended, although progesterone supplementation is suggested by the American Society for Reproductive Medicine and the German, Austrian, and Swiss Society of Gynecology and Obstetrics.

Conclusions

Recurrent pregnancy loss is a devastating condition for couples. Thus, it seems of paramount importance to develop consistent international practice protocols for cost-effective investigation and management of this early pregnancy complication, with the aim to improve live birth rates.

Prevalence of chronic endometritis in patients with infertility due to hydrosalpinx or pelvic peritubal adhesions and effect of laparoscopic surgical correction on pregnancy rates post in vitro fertilization

OBJECTIVE(S)

To assess the prevalence of chronic endometritis (CE) in patients with infertility and hydrosalpinx or peritubal adhesions and to examine the effects of laparoscopic surgical correction (LSC) on CE and pregnancy rates post in vitro fertilization and embryo transfer (IVF-ET).

STUDY DESIGN

This is a retrospective cohort study at private IVF-ET centers. A total of 438 patients, known to have hydrosalpinx (n = 194) or peritubal adhesions (n = 244), and undergoing IVF treatment between April 1, 2018 and September 30, 2020 were included in the study. Hysterosalpingography, magnetic resonance imaging, and transvaginal ultrasonography were used to diagnose the hydrosalpinx or peritubal adhesions. Laparoscopic examination and surgical correction were performed on patients with CE. IVF-ET was performed after recovery from LSC.

RESULTS

CE was present in 45.9% of patients (89/194) with hydrosalpinx and 14.3% with peritubal adhesions (35/244). All the 89 patients with CE and hydrosalpinx underwent laparoscopic salpingostomy and/or fimbrioplasty, and 64 (71.9%) further underwent proximal tubal occlusion. All the 35 patients with CE and peritubal adhesions underwent laparoscopic adhesiolysis and/or fimbrioplasty, and 19 (54.3%) further underwent proximal tubal occlusion. CD138 PC levels after LSC decreased to < 5 in 70 of 124 patients (56.5%) in one menstrual cycle and decreased to < 5 in all cases within 6 months. Of the 66 patients who underwent a single blastocyst transfer, 57 delivered (cumulative live birth rate (LBR): 86.3%). The cumulative LBR of patients treated for CE with LSC (86.3%) was significantly different from those given antibiotic therapy (320 patients; 38.4%; p <.0001) and the CD138-negative groups (811; 31.8%; p <.0001).

CONCLUSION

CE is prevalent in patients with hydrosalpinx and/or peritubal adhesions who present with infertility. LSC improved CE without antibiotic therapy, improving the CP and LBR after IVF-ET.

Comparison of microbial profiles and viral status along the vagina-cervix-endometrium continuum of infertile patients

For decades, the endometrium was considered to be a sterile environment. However, now this concept is disputed, and there is growing evidence that microbiota composition might affect endometrial receptivity. Routine clinical management of infertility is still limited to a microbiological assessment of the lower reproductive tract. The purpose of this study was to compare the abundance of various bacterial, fungal, and viral species, qualitatively and quantitatively, in vaginal, cervical, and endometrial biomaterial of infertile patients. A total of 300 samples from 100 infertile patients of a private assisted reproduction clinic were analyzed. A broad real-time polymerase chain reaction panel was used to identify 28 relevant microbial taxa as well as three members of the Herpesviridae family. All patients underwent endometrial biopsy for further histopathological evaluation. Analysis of the microbial diversity (within the boundaries of the detection panel) revealed that Shannon indexes in the cervix and vagina were similar (1.4 × 10^-2 (1.6 × 10^-3 - 6.5 × 10^-1) vs 1.9 × 10^-2 (2.3 × 10^-3 - 5.3 × 10^-1), respectively, p = 0.502), whereas endometrial indexes differed significantly from both regions (0 (0 - 1.4 × 10^-1), p < 0.0001). Surprisingly, 17 microbial and viral taxa were detected in at least one sample. Endometrium exhibited a quite distinct microbiological profile, being different at the detection rates of 14 taxa (p < 0.05). Remarkably, 4% and 2% of endometrial samples were positive for Cytomegalovirus and Candida spp., respectively, while these were undetectable in corresponding cervical and vaginal samples. Prevalence of the Gardnerella vaginalis + Prevotella bivia + Porphyromonas spp. group in endometrium was associated with a low abundance of Lactobacillus spp. (p = 0.039). No noteworthy associations were identified between various microbiota characteristics and clinical parameters, such as chronic endometritis, uterine polyps and adhesions, endometriosis, and a history of sexually transmitted infections. These findings indicate that the microbiological profile of the endometrium is unique, and the analysis of the lower reproductive tract should supplement, rather than be a substitute for it.

Follicular helper T lymphocytes in the endometria of patients with reproductive failure: Association with pregnancy outcomes and inflammatory status of the endometria

PROBLEM

The phenotypes and functions of B and CD4⁺ T-helper cell subsets during chronic inflammation of the endometria remain largely unexplored. This study aimed to investigate the characteristics and functions of follicular helper T (Tfh) cells to understand the pathological mechanisms of chronic endometritis (CE).

METHOD OF STUDY

Eighty patients who underwent hysteroscopic and histopathological examinations for CE were divided into three groups-those with positive results for hysteroscopy and CD138 staining (DP), negative results for hysteroscopy but positive CD138 staining (SP), and negative results for hysteroscopy and CD138 staining (DN). The phenotypes of B cells and CD4⁺ T-cell subsets were analyzed using flow cytometry.

RESULTS

CD38⁺ and CD138⁺ cells were mainly expressed in the non-leukocyte population of the endometria, and the endometrial CD19⁺ CD138⁺ B cells were fewer than the CD3⁺ CD138⁺ T cells. The percentage of Tfh cells increased with chronic inflammation in the endometria. Additionally, the elevated percentage of Tfh cells correlated with the number of miscarriages.

CONCLUSIONS

CD4⁺ T cells, particularly Tfh cells, may be critical in chronic endometrial inflammation and affect its microenvironment, thereby regulating endometrial receptivity, compared to B cells.

Diagnostic factors for recurrent pregnancy loss: an expanded workup

PURPOSE

There is limited information on the risk factors for recurrent pregnancy loss (RPL).

METHODS

In this study, a patient-based approach was used to investigate the possible involvement and relative relevance of a large number of diagnostic factors in 843 women with RPL who underwent an extensive diagnostic workup including 44 diagnostic factors divided into 7 major categories.

RESULTS

The rates of abnormalities found were: (1) genital infections: 11.74%; (2) uterine anatomic defects: 23.72%; (3) endocrine disorders: 29.42%; (4) thrombophilias: 62%; (5) autoimmune abnormalities: 39.2%; (6) parental karyotype abnormalities 2.25%; (7) clinical factors: 87.78%. Six hundred and fifty-nine out of eight hundred and forty-three women (78.17%) had more than one abnormality. The mean number of pregnancy losses increased by increasing the number of the abnormalities found (r = 0.86949, P < 0.02). The factors associated with the highest mean number of pregnancy losses were cervical isthmic incompetence, anti-beta-2-glycoprotein-1 antibodies, unicornuate uterus, anti-prothrombin A antibodies, protein C deficiency, and lupus anticoagulant. The majority of the considered abnormalities had similar, non-significant prevalence between women with 2 versus ≥ 3 pregnancy losses with the exception of age ≥ 35 years and MTHFR A1298C heterozygote mutation. No difference was found between women with primary and secondary RPL stratified according to the number of abnormalities detected (Chi-square: 8.55, P = 0.07). In these women, the only factors found to be present with statistically different rates were age ≥ 35 years, cigarette smoking, and genital infection by Ureaplasma.

CONCLUSION

A patient-based diagnostic approach in women with RPL could be clinically useful and could represent a basis for future research.

Effect of different antibiotic therapies on the reproductive outcomes of fresh embryo transfer for chronic endometritis: A retrospective cohort study

OBJECTIVE

To investigate the reproductive outcomes by comparing two kinds of antibiotic schemes for chronic endometritis (CE) in infertile women's fresh embryo transfer (FET) cycles and identify subgroups of patients with CE who need long-term antibiotics treatment.

DESIGN

A retrospective cohort study.

SETTING

University-based reproductive medical center.

PATIENT(S)

A total of 492 women with CD138-positive plasmacytes per 10 high-power fields (CD138+/10HPF).

INTERVENTION(S)

Hysteroscopy was performed and endometrial biopsy samples were collected in the proliferative phase. Long-term or short-term antibiotics were administrated. After antibiotics treatment, patients underwent in vitro fertilization (IVF)/ intracytoplasmic sperm injection (ICSI) and received ET.

MAIN OUTCOME MEASURE(S)

Ongoing pregnancy rate, clinical pregnancy rate, clinical miscarriage rate.

RESULT (S)

There were no significant differences in pregnancy outcomes between patients with CD138+/10HPF 1-4 (low-grade CE) who received long-term antibiotic therapy and short-term antibiotics groups. Among women with CD138+/10HPF ≥5 (high-grade CE), live birth rate (48.4% vs. 14.7%, p = .001), clinical pregnancy rate (66.7% vs. 35.3%, p = .002) and ongoing pregnancy rate (59.1% vs. 20.6%, p < .001) in the long-term arm were significantly higher than that in the short-term arm. The clinical miscarriage rate (21.0% vs. 58.3%, p = .013) was statistically lower in the long-term antibiotics group, but no statistical differences were found between the two groups in preterm delivery rate.

CONCLUSION

Long-term antibiotics treatment was a sensible choice to improve pregnancy outcomes in women with CD138+/10HPF ≥5 (high-grade CE). The pregnancy outcomes of women with low-grade CE only defined by histological diagnosis were not greatly improved after antibiotic therapy. Therefore, we recommended the proper diagnosis criteria were CD138+/10HPF ≥5 pathologically.

The association between chronic deciduitis and recurrent pregnancy loss

Chronic deciduitis (CD) is defined as the presence of lymphocytes or plasma cells in decidual tissue. CD suggests the presence of chronic endometritis (CE) which is associated with recurrent pregnancy loss (RPL). In this study, we examined the role CD plays in RPL patients with aneuploid and euploid miscarriage. The frequency of CD in 49 RPL patients (22 euploid and 27 aneuploid miscarriages) and 17 control women was assessed and the subsequent live birth rate (LBR) in the presence and absence of CD were compared. When only one CD138-positive endometrial stromal plasma cell (ESPC) was found per high-power field (HPF), we diagnosed small-positive CD (Grade 1). When a cluster of two or more CD138-positive ESPCs was found per HPF, we diagnosed it as CD Grade 2. The prevalence of Grade 1 was 18.2% (4/22) in patients with euploid miscarriage, 37.0% (10/27) in patients with aneuploid miscarriage and 23.5% (4/17) in control women. The prevalence of Grade 2 was 45.5% (10/22) in patients with euploid miscarriage, 55.6% (15/27) in patients with aneuploid miscarriage and 23.5% (4/17) in control women. There was a significant difference in the prevalence of CD (p = 0.015). The LBR of patients with CD was similar to that of patients without CD. CD was associated with RPL, especially in patients with aneuploid miscarriage. However, since there was no difference in the LBR of patients with or without CD in the next pregnancy, it was unclear whether CD was a contributing cause of RPL.

The prevalence of endometrial polyp in women with tubal factor infertility is higher than male factor infertility: Is PID one of the causes of endometrial polyp?

AIMS

Previous studies have shown an association between chronic endometritis and endometrial polyps, and only one study in infertile women reported an association between tubal obstruction and polyps. This study aimed to compare the prevalence of endometrial polyps in two groups of women with tubal factor infertility and male factor infertility to assess if is there any association between tubal factor infertility and endometrial polyps.

METHODS

This case-control study was performed on infertile women. The case group included women with tubal factor infertility and the control group included all women with male factor infertility. In all patients, vaginal ultrasound was performed between days 8 and 12 of the menstrual cycle to diagnose endometrial polyp, its size, and number. Demographic and obstetrics variables were recorded. Patients underwent hysteroscopy and polypectomy and the diagnosis of the polyp was confirmed by pathology report.

RESULT

In the present study, 245 people participated in two groups. There was a statistically significant difference between the two groups in terms of demographic and obstetric characteristics like type of infertility, duration of infertility, and gravidity. The prevalence of polyps in the tubal factor group was higher than in the male factor group (63 [60%] vs. 12 [9.8%]), and this difference was statistically significant (p = 0.0001). In addition, the prevalence of chronic endometritis in the tubal factor group was higher than in the male factor group (19 [18.8%] vs. 4 [3.3%]), and this difference was statistically significant (p = 0.001).

CONCLUSIONS

In the present study, a strong association was observed between endometrial polyps and tubal obstruction, and considering that the most common cause of tubal obstruction is pelvic and genital infections, after confirmation with more studies, it may be possible to consider antibiotic treatment in these patients, especially in patients with recurrent polyps.

Exosomes From Adipose-Derived Stem Cells Suppress the Progression of Chronic Endometritis

Chronic endometritis (CE) is closely linked to the reproductive failure. Exosome (Exo)-based therapy is proposed as an encouraging strategy in inflammation-related disorders; however, little work has been devoted to its usage in CE therapy. An in vitro CE was established by administration of lipopolysaccharide (LPS) in human endometrial stromal cells (HESCs). The cell proliferation, cell apoptosis, and inflammatory cytokine assays were performed in vitro, and the efficacy of Exos derived from adipose tissue-derived stem cells (ADSCs) was evaluated in a mouse model of CE. We found that Exos isolated from ADSCs could be taken up by HESCs. Exos elevated the proliferation and inhibited apoptosis in LPS-treated HESCs. Administration of Exos to HESCs suppressed the content of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β). Moreover, Exos exposure repressed the inflammation stimulated by LPS in vivo. Mechanistically, we demonstrated that Exos exerted their ant-inflammatory effect via miR-21/TLR4/NF-kB signaling pathway in endometrial cells. Our findings suggest that ADSC-Exo-based therapy might serve as an attractive strategy for the treatment of CE.

Endometriosis and dysbiosis: State of art

Endometriosis is a complex and heterogeneous disease affecting approximately 10% of reproductive age women. The hypothesis that alterations in the microbiota are involved in the pathogenesis of endometriosis has been postulated. Possible explanations for the implications of dysbiosis in endometriosis include the Bacterial Contamination hypothesis and immune activation, cytokine-impaired gut function, altered estrogen metabolism and signaling. Thus, dysbiosis, disrupt normal immune function, leading to the elevation of proinflammatory cytokines, compromised immunosurveillance and altered immune cell profiles, all of which may contribute to the pathogenesis of endometriosis. The aim of this review is to summarize the available literature data about the relationship between microbiota and endometriosis.

The effectiveness of intrauterine antibiotic infusion versus oral antibiotic therapy in the treatment of chronic endometritis in patients during IVF (in vitro fertilization) procedures

BACKGROUND

Chronic Endometritis (CE) is a subtle pathology, likely infectious in most cases, with a negative impact on the female fertility, but often overlooked even among fertility specialists. The purpose of the study is to demonstrate the predominant infectious nature of CE and to find the best therapeutic option by comparing the results of oral antibiotic therapy versus intrauterine antibiotic infusion in patients with CE undergoing IVF procedures. The objective was to compare the cure rate of CE-defined as the percentage of patients without CE at the test of cure, between the two groups and, the hysteroscopic aspect with the positive CD 138 staining.

METHODS

This was a prospective, case-control study that took place in a single university fertility clinic, in Oradea, Romania and included 57 patients with CE divided into 2 groups: orally administered antibiotics group who received a combination of antibiotics compared to intrauterine infusion group who received intrauterine infusion of antibiotic. Chronic Endometritis was diagnosed through hysteroscopy and immunohistochemistry for CD 138. Patients in both groups were tested for CE twice to evaluate the cure rate after oral combination antibiotic therapy versus intrauterine infusion of antibiotic.

RESULTS

Out of 115 patients with endometrial biopsies 57 tested positive for CE, with a 49.6% chronic endometritis prevalence. Among the group that was administered oral antibiotics, 11 patients (45.83%) experienced CE resolution after triple antibiotic therapy. Of the intrauterine infusion group, 25 patients (89.29%) presented negative results (p 0.0020). The normal hysteroscopic aspect had a similar prevalence in the patients with immunohistochemical positive and negative CD 138.

CONCLUSIONS

Our study demonstrated the effectiveness and superiority of intrauterine antibiotic infusion over the use of oral combination antibiotic therapy for CE cure.

TRIAL REGISTRATION

ISRCTN17542620/14.09.2022.

Association between hysteroscopic features of chronic endometritis and pregnancy outcomes of patients after in vitro fertilization: a retrospective cohort study

This retrospective cohort study explored the morphological features of chronic endometritis (CE) and pregnancy outcomes during in vitro fertilization (IVF) in women with CE (429) at Yantai Yuhuangding Hospital between January 2017 and September 2018. The primary outcome was the clinical pregnancy rate (CPR). The women displayed haemorrhagic spots (175), hyperaemia (122), micropolyps (75), hyperaemia combined with micropolyps (49) and others (8). The CPR and live birth rate (LBR) were different among the hysteroscopic features of CE in fresh embryo transfer cycles (p = .002, p = .011). The miscarriage and premature birth rates were not significantly different among groups (p > .05). Hyperaemia (0.47 [95% CI, 0.29; 0.77]), micropolyps (0.40 [95% CI, 0.23; 0.72]), hyperaemia combined with micropolyps (0.35 [95% CI, 0.18; 0.69]) and others (0.36 [95% CI, 0.19; 0.69]) were associated with the CPR. In conclusion, the hysteroscopic features of CE are associated with IVF pregnancy outcomes, and there were differences in pregnancy outcomes with different CE hysteroscopic features.IMPACT STATEMENTWhat is already known on this subject? Chronic endometritis (CE) is associated with adverse pregnancy outcomes such as infertility, premature delivery and miscarriage. CE can reduce the success rate of pregnancy and even lead to obstetric and neonatal complications, and is an adverse factor for the success of in vitro fertilization (IVF). There are different types of CE, but their impact on IVF outcomes is unknown.What the results of this study add? The CPR and LBR were different among the hysteroscopic features of CE in fresh embryo transfer cycles (p = .002, p = .011). The miscarriage and premature birth rates were not significantly different among groups (p > .05). After adjustment, the multivariable analysis showed that hyperaemia (OR = 0.47, p = .002), micropolyps (OR = 0.40, p = .002), hyperaemia combined with micropolyps (OR = 0.35, p = .002) and others (OR = 0.36, p = .002) were associated with the CPR among patients with CE.What the implications are of these findings for clinical practice and/or further research? The hysteroscopic features of CE are associated with IVF pregnancy outcomes, and there were differences in pregnancy outcomes with different CE hysteroscopic features. Hence, women with repeated IVF failure should undergo hysteroscopy to examine for the presence of CE and its nature.

Effects of Hydrosalpinx on Endometrial Receptivity and Uterine Microbiome: An Interesting Case of Double Uterus with Unilateral Hydrosalpinx

Endometrial receptivity array (ERA)—an objective tool used in assisted reproductive technology—is used for personalized embryo transfer in in vitro fertilization. Hydrosalpinx affects implantation through various mechanisms. However, its effects on ERA are not well established. In this case report, we present the diagnosis and treatment of a 34-year-old nulligravida woman with infertility for two years, obesity, double uterus with unilateral hydrosalpinx and right kidney deficiency. Based on ERA results, endometrial microbiome metagenomic analysis (EMMA), analysis of infectious chronic endometritis (ALICE), and CD138 immunostaining, the patient was treated with hormonal replacement cycle and amoxicillin/clavulanic acid. After one week of amoxicillin/clavulanic acid administration, the vitirified-warmed 4AA blastocyst was transferred to the left uterus—which was absent of hydrosalpinx and easily accessible to transfer and pregnancy was achieved. To the best of our knowledge, this case study is the first one in which we found that there were no differences between the left and right uterus in ERA, EMMA, ALICE, and CD138 immunostainings. Hence, we suggest that hydrosalpinx does not necessarily cause endometrial changes in all cases. Further research to evaluate the effects of hydrosalpinx on implantation with ERA and EMMA/ALICE is warranted.

Recurrent Miscarriage: Diagnostic and Therapeutic Procedures. Guideline of the DGGG, OEGGG and SGGG (S2k-Level, AWMF Registry No. 015/050, May 2022)

Purpose The aim of this guideline is to standardize the diagnosis and therapy of recurrent miscarriage (RM) using evidence from the recent literature. This is done by using consistent definitions, objective evaluations and standardized treatment protocols.

Methods When this guideline was compiled, special consideration was given to previous recommendations in prior versions of this guideline and the recommendations of the European Society of Human Reproduction and Embryology, the Royal College of Obstetricians and Gynecologists, the American College of Obstetricians and Gynecologists and the American Society for Reproductive Medicine, and a detailed individual search of the literature about the different topics was carried out.

Recommendations Recommendations about the diagnostic and therapeutic procedures offered to couples with RM were developed based on the international literature. Special attention was paid to known risk factors such as chromosomal, anatomical, endocrinological, physiological coagulation, psychological, infectious and immune disorders. Recommendations were also developed for those cases where investigations are unable to find any abnormality (idiopathic RM).

Impact of antibiotic treatment for chronic endometritis on pregnancy outcomes in women with reproductive failures (RIF and RPL): A systematic review and meta-analysis

Objective

The aim of this study was to investigate the effect of antibiotic treatment for chronic endometritis (CE) on reproductive outcomes.

Design

Systematic review and meta-analysis.

Patients

Women with reproductive failures, including recurrent implantation failure (RIF), and recurrent pregnancy loss (RPL).

Interventions

Literature searches were performed using three electronic databases (PubMed, Embase, and Web of Science) until 1 December 2021 (without date restriction). The following comparators were included: women with CE receiving antibiotics vs. untreated controls; women with cured CE vs. women with normal endometrial histology (negative for CE); and women with cured CE vs. women with persistent CE (PCE). The summary measures were indicated as odds ratio (OR) with a 95% confidence interval (CI).

Main outcome measures

These include on-going pregnancy rate/live birth rate (OPR/LBR), clinical pregnancy rate (CPR), and miscarriage rate/pregnancy loss rate (MR/PLR).

Results

A total of 2,154 women (from twelve studies) were enrolled. Compared with the control group, women with CE receiving antibiotics did not show a statistically significant difference in OPR/LBR (P = 0.09) and CPR (P = 0.36), although there was a lower MR (P = 0.03). Women with cured CE have higher OPR/LBR (OR 1.57) and CPR (OR 1.56) in comparison with those with non-CE. There was a statistically significantly higher OPR/LBR (OR 6.82, P < 0.00001) and CPR (OR 9.75, P < 0.00001) in women with cured CE vs. those with persistent CE.

Conclusion

While antibiotic treatment is a sensible option to cure CE, more well-designed prospective studies are needed to evaluate the reproductive impact of antibiotic treatment. Cured CE provides high-quality maternal conditions for subsequent embryo transfer and successful pregnancy.

Microbial Diversity and Pathogenic Properties of Microbiota Associated with Aerobic Vaginitis in Women with Recurrent Pregnancy Loss

Recurrent pregnancy loss (RPL) is a major reproductive problem that affects approximately 5% of couples. The objective of this study was to assess vaginal flora dysbiosis in women suffering from unexplained RPL and to investigate the pathogenic properties of the microbiota associated with aerobic vaginitis (AV). The study included one hundred fifteen women, 65 with RPL and 50 controls. The diversity of vaginal microbiota isolated was evaluated by molecular sequencing. Then, pathogenic factors, such as acid-resistance, antibiotics susceptibility, and biofilm formation were evaluated. The prevalence of AV was five-fold higher in the RPL group than in the controls (64.6% vs. 12.0%). The most prevalent isolates in the case group were Enterococcus spp. (52%) and Staphylococcus spp. (26%). All bacterial strains tolerate low pH. The prevalence of multidrug resistance (MDR) among all bacteria was 47.7%. Of all strains, 91.0% were biofilm producers. The presence of MDR was found to be related to biofilm formation. The results provide evidence supporting an increased presence of dysbiosis of the vaginal flora, especially AV, in women with RPL in Tunisia. The viability of the AV-associated bacteria and their persistence in the genitals may be due to their ability to resist low pH and to produce a biofilm.

The menstrual cycle phase impacts the detection of plasma cells and the diagnosis of chronic endometritis in endometrial biopsy specimens

OBJECTIVE

To assess the impact of menstrual cycle phase on the detection of plasma cells.

DESIGN

A retrospective cohort study.

SETTING

Fertility clinic.

PATIENT(S)

Biopsies from 157 patients met criteria for inclusion, 91 in the follicular phase and 60 in the luteal phase. Patient groups were similar in body mass index and number of previous live births; however, differed in terms of age, infertility history, and biopsy indication.

INTERVENTIONS

Endometrial biopsies from patients at a fertility clinic from 2018-2020 were retrospectively reviewed. Biopsies were excluded if patients had a previous chronic endometritis diagnosis, abnormal uterine cavity or were on hormone therapy. Each case was reviewed by a gynecologic pathologist for plasma cells by hematoxylin and eosin and CD138 staining. Demographic and clinical data were collected. Continuous variables were compared using Welch t test and Wilcoxon's rank sum test, and categorical variables using Pearson's χ² test. Logistic regression was used to calculate odds ratio and 95% confidence intervals for the association between the presence of plasma cells and cycle phase. Multinomial logistic regression was used to estimate the odds ratios for nominal outcomes. Pathology reports were reviewed. Plasma cell enumeration using hematoxylin and eosin-stained sections and CD138 immunohistochemical stains (performed at the time of biopsy by a gynecologic pathologist) was recorded.

MAIN OUTCOME MEASURE(S)

Presence and density of plasma cells.

RESULT(S)

We found a higher likelihood of finding plasma cells in the follicular than in luteal phase (59.3% vs. 19.7%). There was a higher likelihood of finding plasma cells in the early (cycle days 5-8, 29 cases or 76.3% of cases with plasma cells) than in the late follicular phase (cycle days 9-14, 25 cases or 47.2%). There was a higher density of plasma cells in the follicular phase group than in the luteal phase group (25.3% vs. 1.5% scattered and 13.2% vs. 0 clusters).

CONCLUSION(S)

Plasma cells are more likely to be present during the follicular phase compared with the luteal phase and in the early compared with the late follicular phase. Further studies are needed to identify the optimal timing of biopsy to standardize the diagnosis.

Retained pregnancy tissue after miscarriage is associated with high rate of chronic endometritis

The objective of this study was to evaluate prevalence of chronic endometritis in a cohort of patients with retained pregnancy tissue (RPT) following miscarriage, with and without a history of recurrent pregnancy loss (RPL). In a cohort of our single academic fertility centre, we evaluated women with unexplained RPL (two or more losses) without evidence of RPT and women undergoing hysteroscopic resection of RPT following miscarriage. Endometrial samples underwent staining with H and E and CD138. A pathologist blinded to patient history recorded the number of plasma cells per 10 high power fields (HPF) and the presence or absence of endometrial stromal changes. Our main outcome measure was to measure the prevalence of chronic endometritis. Endometrial samples from 50 women with RPT following miscarriage and 50 women with unexplained RPL without evidence of RPT were reviewed. The prevalence of chronic endometritis was significantly higher in the RPT cohort (62% versus 30%). A multivariable regression demonstrated significantly higher odds of chronic endometritis in the RPT cohort, aOR 7.3 (95% CI 2.1, 25.5). We conclude that women with RPT following pregnancy loss have a high rate of chronic endometritis, suggesting that RPT is a risk factor for this disorder. Impact StatementWhat is already known on this subject? Known risk factors for chronic endometritis include a history of pelvic inflammatory disease, intrauterine polyps and fibroids. The aetiology for increased chronic endometritis among women with RPL is unknown.What do the results of this study add? The prevalence of chronic endometritis is significantly higher among women with retained pregnancy tissue (RPT) following miscarriage compared to women with RPL. These data presented suggest that RPT is associated with chronic endometritis among women with a history of miscarriage.What are the implications of these findings for clinical practice and/or further research? We suggest a pathologic evaluation for chronic endometritis be performed on all patients who undergo hysteroscopic resection of RPT following miscarriage. Our findings also suggest that a uterine cavity evaluation with hysteroscopy to evaluate for RPT may be reasonable in women with a history of miscarriage who are found to have chronic endometritis on endometrial biopsy. Further research is needed to determine if resection of retained tissue is sufficient to treat RPOC associated chronic endometritis, or if additional antibiotic treatment is necessary.

Vaginom- und „Endometriom“-Diagnostik bei Kinderwunsch

Die molekulare Diagnostik der Vaginal- und Endometriumflora ermöglicht neue Einblicke in die physiologische Besiedlung des weiblichen Genitaltrakts. Wesentlich ist hierbei eine Dominanz von bestimmten Laktobazillenarten bei gleichzeitig geringer Artenvielfalt. Die Bildung von D‑Laktat ist eine entscheidende Voraussetzung für die Abwehr von sexuell übertragbaren Erkrankungen, den Erfolg einer In-vitro-Fertilisation sowie einen ungestörten Schwangerschaftsverlauf. Eine Störung der Flora durch pathogene Bakterienarten mit der Folge des Auftretens einer bakteriellen Vaginose oder einer chronischen Endometritis kann zu Implantationsversagen, Aborten und Frühgeburtsbestrebungen führen. Bei wiederholtem Implantationsversagen ermöglicht eine Mikrobiomdiagnostik – im Gegensatz zur klassischen Kultur, den Amsel-Kriterien oder dem Nugent-Score – einen sehr viel detaillierteren Einblick in die Pathophysiologie, da sich entscheidende Bakterienarten nur schwer oder gar nicht anzüchten lassen. Dies erlaubt eine sehr viel bessere Planung der Therapie zur Wiederherstellung physiologischer Verhältnisse.

Research update for the immune microenvironment of chronic endometritis

Chronic endometritis (CE) is a persistent and subtle local inflammatory disease characterized by abnormal plasma cell infiltration in the endometrial stroma.The incidence of chronic endometritis is as high as 15-57.5% in women suffering from infertility, implantation failure of in vitro fertilization (IVF) and unexplained recurrent abortion. Many studies both at home and abroad have shown that CE can reduce the receptivity of endometrium and affect embryo implantation. According to the existing reproductive immunity research, the abnormality of immune cell subsets in endometrium is an important factors leading to pregnancy failure. The immune microenvironment in endometrium consists of immune cells and immune molecules, and their influence on embryo implantation can not be ignored. This review paper discusses the controversy of pathogenesis, diagnosis and treatment of CE from the perspective of immune microenvironment by referring to related literature at home and abroad, and investigates the possible ways to improve the diagnosis and treatment of CE.

Investigation of the Relationship between Chronic Endometritis Manifestations under Hysteroscope and CD138 Expression

Methods

This study was performed to retrospectively analyze clinical cases of 523 CE patients from January 2018 to June 2020 that were confirmed by hysteroscopy before in vitro fertilization. Based on manifestations of CE under hysteroscopy, the cases were divided into three cohorts, i.e., hyperemia cohort where the patients had diffuse endometrium hyperemia; endometrial micropolyp cohort, and endometrial stroma edema and hyperplasia cohort. Small amount of endometrial tissue was collected from the patients, and CD138 IHC examination was performed. According to the results of CD138 IHC, positive patients were given antibiotic treatment (doxycycline 100 mg BID orally for 14 days), and hysteroscopy was performed again after treatment to check the efficacy of antibiotics.

Results

In the comparison of overall status for all patient cohorts, infertility type, BMI, bFSH, bLH, bP, bT, PRL, AMH, and CA125 were varied markedly across all cohorts (P < 0.05), with predominant incidences of polycystic ovary syndrome (PCOS) peaking within hyperemia cohort. Incidence/diagnostic rate for CD138 within hyperemia cohort was 10.06%, which was lower than the 63.16% in micropolyp cohort and 74% in edema and hyperplasia cohort (P < 0.05). No major variation existed within CD138 across micropolyp cohort/edema and hyperplasia cohort (P > 0.05). After CD138-positive CE patients were treated with antibiotics, the effective rate (0/16) within hyperemia cohort was lower than micropolyp cohort (73.61%, 53/72) and edema and hyperplasia cohort (83.24%, 154/185) (P < 0.05). The effective rate across micropolyp cohort/edema and hyperplasia cohort was not significantly different (P > 0.05).

Conclusion

Cases of diffuse endometrial hyperemia under hysteroscope had the lowest positive rate of CD138, and the effect of antibiotic treatment on these patients was poor. The positive rate of CD138 in patients with endometrial micropolyps and endometrial stroma edema and hyperplasia under hysteroscope was high, and the effect of antibiotic treatment was better.

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.

Diagnosing chronic endometritis: when simplification fails to clarify

Reproductive immunology has grown in importance in recent years and has even developed into a discipline of its own within the field of reproductive medicine. Many aspects of reproductive failure such as repeated implantation failure or recurrent miscarriages are, meanwhile, seen as a consequence of aberrant expression of immunological factors. This is reflected by the increasing number of tests for assessing and quantifying different immune cell types as well as by a wide range of immune therapies offered to a clientele consisting of desperate patients requesting additional ‘IVF tools’: first, what is still usually disregarded is the enormous plasticity and fluctuation of most immune cells in the genital tract; second, their still poorly characterized functions in the endometrial cycle: further, their partially unknown role in embryo implantation and in establishing a pregnancy; and third, the fact that one of the fundamental hypotheses of reproductive immunology—of note—the Medawar concept or ‘Medawar's Paradox’ of semi-allogeneic graft embryo, is partially based on an erroneous assumption, i.e. the immunologic rejection and tolerance of an embryo. In the present opinion article, we comment on the diagnostic procedures and therapy approaches for chronic endometritis within the scope of reproductive medicine.

Derangements of vaginal and cervical canal microbiota determined with real-time PCR in women with recurrent miscarriages

Balanced vaginal microbiota and, as a continuum, cervical canal microbiota help prevent reproductive disorders, including recurrent miscarriage (RM). In a significant proportion of couples with RM, routine diagnostic workup cannot find any manageable cause, leading to a requirement for new diagnostic tools. In the present study, we determined the quantitative composition of the microbiota of the vagina and cervical canal, assessed by real-time polymerase chain reaction, in women with RM. It also evaluated their derangements related to the pathogenesis of RM, and thus the suitability of this test as a diagnostic tool for managing RM. Vaginal and cervical canal specimens of 25 women with RM and 25 healthy volunteers were collected. The test results revealed information about the total vaginal bacterial biomass by measuring the abundance of Lactobacillus spp.; other bacteria; and pathogens, including Mycoplasma hominis, Mycoplasma genitalium, Ureaplasma (urealyticum + parvum), and Candida spp. Overall, the findings of this study implied the abundance of Lactobacillus spp. decreased in women with RM with an increase in the abundance of other microorganisms in accordance with the reduction in the abundance of Lactobacillus spp. due to aerobic vaginitis and bacterial vaginosis. Vaginal and cervical canal microbiota need to be considered during the diagnostic workup of women with RM.IMPACT STATEMENTWhat is already known on this subject? Recurrent miscarriage (RM) is a well-known reproductive disorder. Its diagnostic workup is not successful in determining the underlying problem in many cases. Hence, novel diagnostic tools based on real-time polymerase chain reaction (PCR) are needed for evaluating reproductive microbiota, which are considerably reliable, to satisfy the expectations of women with RM.What do the results of this study add? Overall, the decrease in the abundance of Lactobacillus spp. was found to be related to RM, and the patterns of the presence of other microorganisms were in accordance with the reduction in the abundance of Lactobacillus spp. These findings suggested an important role of vaginal and cervical canal microbiota in the pathogenesis of RM.What are the implications of these findings for clinical practice and/or further research? Additional research is warranted to elucidate the functional impact of altered components of the microbiota of vaginal and cervical canals on the physiology of the local cervical canal and its participation in the microbiota of the endometrial cavity, especially regarding unsuccessful pregnancies as a result of the disturbed physiology of the local endometrial microenvironment. However, possible applications of real-time PCR-based tests for the screening of subclinical infections in clinical practice require the performance of further investigations in patients with RM.

Differences in microbial profile of endometrial fluid and tissue samples in women with in vitro fertilization failure are driven by Lactobacillus abundance

INTRODUCTION

The endometrial microbiota has been linked to several gynecological disorders, including infertility. It has been shown that the microbial profile of endometrium could have a role in fertilization and pregnancy outcomes. In this study we aim to assess the microbial community of endometrial tissue (ET) and endometrial fluid (EF) samples in women receiving in vitro fertilization (IVF) treatment. We also search for possible associations between chronic endometritis (CE) and endometrial microbiota.

MATERIAL AND METHODS

This was a cohort study involving 25 women aged between 28 and 42 years with both primary and secondary infertility and with at least one IVF failure. The ET and EF sample collection was carried out between September 2016 and November 2018. Each of the participants provided two types of samples-tissue and fluid samples (50 samples in total). A 16S rRNA sequencing was performed on both of the sample types for microbial profile evaluation. CE was diagnosed based on a CD138 immunohistochemistry where CE diagnosis was confirmed in the presence of one or more plasma cells. Microbial profiles of women with and without CE were compared in both sample types separately.

RESULTS

We report no differences in the microbial composition and alpha diversity (p_Observed  = 0.07, p_Shannon  = 0.65, p_{Inverse Simpson}  = 0.59) between the EF and ET samples of IVF patients. We show that the abundance of the genus Lactobacillus influences the variation in microbial beta diversity between and fluid samples (r²  = 0.34; false discovery rate [FDR] <9.9 × 10^-5 ). We report that 32% (8/25) of the participants had differences in Lactobacillus dominance in the paired samples and these samples also present a different microbial diversity (p_Shannon  = 0.06, FDR_{weighted UniFrac}  = 0.01). These results suggest that the microbial differences between ET and fluid samples are driven by the abundance of genus Lactobacillus. The microbiome of CE and without CE (ie non-CE) women in our sample set of IVF patients was similar.

CONCLUSIONS

Our findings show that genus Lactobacillus dominance is an important factor influencing the microbial composition of ET and fluid samples.

A More Diverse Cervical Microbiome Associates with Better Clinical Outcomes in Patients with Endometriosis: A Pilot Study

Infection-induced chronic inflammation is common in patients with endometriosis. Although microbial communities in the reproductive tracts of patients have been reported, little was known about their dynamic profiles during disease progression and complication development. Microbial communities in cervical mucus were collected by cervical swabs from 10 healthy women and 23 patients, and analyzed by 16S rRNA amplicon sequencing. The abundance, ecological relationships and functional networks of microbiota were characterized according to their prevalence, clinical stages, and clinical features including deeply infiltrating endometriosis (DIE), CA125, pain score and infertility. Cervical microbiome can be altered during endometriosis development and progression with a tendency of increased Firmicutes and decreased Actinobacteria and Bacteroidetes. Distinct from vaginal microbiome, upregulation of Lactobacillus, in combination with increased Streptococcus and decreased Dialister, was frequently associated with advanced endometriosis stages, DIE, higher CA125 levels, severe pain, and infertility. Significantly, reduced richness and diversity of cervical microbiome were detected in patients with more severe clinical symptoms. Clinical treatments against infertility can partially reverse the ecological balance of microbes through remodeling nutrition metabolism and transport and cell-cell/cell-matrix interaction. This study provides a new understanding on endometriosis development and a more diverse cervical microbiome may be beneficial for patients to have better clinical outcomes.

MUM-1 immunohistochemistry has high accuracy and reliability in the diagnosis of chronic endometritis: a multi-centre comparative study with CD-138 immunostaining

PURPOSE

The current gold standard for chronic endometritis (CE) diagnosis is immunohistochemistry (IHC) for CD-138. However, IHC for CD-138 is not exempt from diagnostic limitations. The aim of our study was to evaluate the reliability and accuracy of MUM-1 IHC, as compared with CD-138.

METHODS

This is a multi-centre, retrospective, observational study, which included three tertiary hysteroscopic centres in university teaching hospitals. One hundred ninety-three consecutive women of reproductive age were referred to our hysteroscopy services due to infertility, recurrent miscarriage, abnormal uterine bleeding, endometrial polyps or myomas. All women underwent hysteroscopy plus endometrial biopsy. Endometrial samples were analysed through histology, CD138 and MUM-1 IHC. The primary outcome was to evaluate the diagnostic accuracy of MUM-1 IHC for CE, as compared with CD-138 IHC.

RESULTS

Sensitivity and specificity of CD-138 and MUM-1 IHC were respectively 89.13%, 79.59% versus 93.48% and 85.03%. The overall diagnostic accuracy of MUM-1 and CD-138 IHC were similar (AUC = 0.893 vs AUC = 0.844). The intercorrelation coefficient for single measurements was high between the two techniques (ICC = 0.831, 0.761-0.881 95%CI). However, among CE positive women, MUM-1 allowed the identification of higher number of plasma cells/hpf than CD-138 (6.50 [SD 4.80] vs 5.05 [SD 3.37]; p = 0.017). Additionally, MUM-1 showed a higher inter-observer agreement as compared to CD-138.

CONCLUSION

IHC for MUM-1 and CD-138 showed a similar accuracy for detecting endometrial stromal plasma cells. Notably, MUM-1 showed higher reliability in the paired comparison of the individual samples than CD-138. Thus, MUM-1 may represent a novel, promising add-on technique for the diagnosis of CE.