Chronic endometritis in women with recurrent early pregnancy loss and/or fetal demise

Impact of Diagnosis and Treatment of Chronic Endometritis on Outcomes Before Starting Assisted Reproductive Technology: A Retrospective Study

This study aimed to investigate the effect of diagnosis and treatment of chronic endometritis (CE) on the outcome of assisted reproductive technology (ART) with or without repeated implantation failure (RIF). This retrospective analysis included patients who underwent pathological examination for diagnosis of CE at Yamagata University Hospital. The examination was performed for all patients planned for ART with or without RIF. Patients who were examined within 6 months of the first oocyte retrieval or embryo transfer were included. We counted the number of CD138-positive cells within the endometrial stroma in patients' specimens and analyzed the patients' clinical information. Clinical rates of pregnancy and implantation were determined. A total of 80 women met the inclusion criteria: 13 CE-negative patients (17.3%) and 67 CE-positive patients (83.7%). A significant decrease was noted in the CD138-positive cell count between the first biopsy and second biopsy after CE treatment (p < 0.001). In addition, no significant differences were noted in ongoing pregnancy rates between the CE-negative patients and those who underwent CE treatment. The CD138-positive cell counts at first biopsy tended to be lower in each pregnancy group than in the non-pregnancy group. For patients planned to undergo ART, examination for diagnosis of CE with or without RIF could be considered. Pathological CD138-positive cell counts were considered useful for CE diagnosis and treatment decision-making. The study findings suggest the efficacy of antimicrobial agents in CE treatment, contributing to improved pregnancy outcomes.

Intrauterine Shaping of Fetal Microbiota

Mechanisms resulting from the physiological immaturity of the digestive system in children delivered before 32 weeks of gestation and, in particular, different interactions between the microbiome and the body have not been fully elucidated yet. Next-generation sequencing methods demonstrated the presence of bacterial DNA in the placenta and amniotic fluid, which may reflect bacterial populations that initiate intestinal colonization in utero. Numerous studies confirmed the hypothesis stating that intestinal bacteria played an important role in the pathogenesis of necrotizing enterocolitis (NEC) early- and late-onset neonatal sepsis (EONS and LONS). The model and scale of disorders within the intestinal microbiome are the subject of active research in premature infants. Neonatal meconium was primarily used as an indicator defining the environment in utero, as it is formed before birth. Metagenomic results and previous data from microbiological bacterial cultures showed a correlation between the time from birth to sample collection and the detection of bacteria in the neonatal meconium. Therefore, it may be determined that the colonization of the newborn's intestines is influenced by numerous factors, which may be divided into prenatal, perinatal, and postnatal, with particular emphasis put on the mode of delivery and contact with the parent immediately after birth. Background: The aim of this review was to collect available data on the intrauterine shaping of the fetal microbiota. Methods: On 13 March 2024, the available literature in the PubMed National Library of Medicine search engine was reviewed using the following selected keywords: "placental microbiome", "intestinal bacteria in newborns and premature infants", and "intrauterine microbiota". Results: After reviewing the available articles and abstracts and an in-depth analysis of their content, over 100 articles were selected for detailed elaboration. We focused on the origin of microorganisms shaping the microbiota of newborns. We also described the types of bacteria that made up the intrauterine microbiota and the intestinal microbiota of newborns. Conclusions: The data presented in the review on the microbiome of both term newborns and those with a body weight below 1200 g indicate a possible intrauterine colonization of the fetus depending on the duration of pregnancy. The colonization occurs both via the vaginal and intestinal route (hematogenous route). However, there are differences in the demonstrated representatives of various types of bacteria, phyla Firmicutes and Actinobacteria in particular, taking account of the distribution in their abundance in the individual groups of pregnancy duration. Simultaneously, the distribution of the phyla Actinobacteria and Proteobacteria is consistent. Considering the duration of pregnancy, it may also be concluded that the bacterial flora of vaginal origin dominates in preterm newborns, while the flora of intestinal origin dominates in term newborns. This might explain the role of bacterial and infectious factors in inducing premature birth with the rupture of fetal membranes.

Viral Infection in Endometritis: Is There an Important Role or Not?

Chronic endometritis (CE) is a frequent pathological condition that is defined as localized inflammation in the endometrium. Some adverse fertility consequences such as recurrent miscarriage and failure of implantation are associated with chronic endometritis. On the one hand, inflammation plays an important role in the pathogenesis of endometritis, and on the other hand, the role of viral infections in inducing inflammation can make this review strongly attractive and practical. We set out to provide an overview of viral infections as a potential etiology of CE pathophysiology through the alteration of an endometrial microenvironment and its association with infertility. To the best of our knowledge, this is the first review to demonstrate the role of viral infection in chronic endometritis, and whether or not infection ultimately plays a role..

The role and challenges of regulating endometrial microbiome in uterine health and diseases

The uterine environment provides necessary conditions for the existence of endometrial microbiota, which in turn plays an important role in maintaining the homeostasis of the uterine environment. The endometrial microbiome is highly susceptible to external factors such as age, hormones, menstrual, pregnancy, etc. When the microbiota is imbalanced, it will further promote the occurrence of uterine diseases such as endometritis and endometrial cancer. Regulating the microbiome of the endometrium is of positive significance for promoting uterine health. Among them, antibiotics, probiotics, prebiotics, and microbial transplantation may be important pathways for regulating endometrial microbiota in the future. However, there is currently no unified plan for evaluating the endometrial microbiota. In addition, due to the small sample size, it is easy to be contaminated by exogenous bacterial DNA, which poses great challenges for studying the mechanism of microbial community regulating uterine health. Therefore, there are still many areas worth exploring for the future of endometrial microbiome.

Chronic endometritis and recurrent reproductive failure: a systematic review and meta-analysis

Background

The endometrium holds a crucial role in reproduction by supporting blastocyst adhesion, cytotrophoblast invasion and fetal development. Among the various uterine disorders, endometritis, particularly chronic endometritis (CE), has gained attention due to its association with adverse reproductive outcomes (recurrent pregnancy loss (RPL), recurrent implantation failure (RIF), and infertility). The association between CE and adverse reproductive outcomes stresses the necessity for comprehensive diagnostic and therapeutic strategies to optimize fertility outcomes and support individuals in their journey towards parenthood.

Aim

To explore the relationship between CE and reproductive disorders.

Methods

Following PRISMA guidelines, a systematic review and meta-analysis using published data from 1990 to 2024 were carried out.

Results

A population of 1,038 women was included. Regarding CE-infertility association, a positive correlation was found, with 19.46% CE rate in infertile women compared to 7.7% in controls (OR: 2.96, 95% CI 1.53-5.72, p 0.001). No significant association was observed between RIF and CE (OR: 1.10, 95% CI 0.26-4.61, p 0.90), CE rates in both groups were relatively comparable, with 6.35% in women with RIF and 5.8% in controls. On the opposite, a strong association between CE and RPL was found, reporting a CE rate of 37.6% in RPL cases compared to 16.4% in controls (OR: 3.59, 95% CI 2.46-5.24, p < 0.00001).

Conclusions

CE appears to be associated to infertility and RPL, while no significant association was noted in cases of RIF.

Systematic review registration

https://www.crd.york.ac.uk/prospero/#recordDetails PROSPERO, identifier CRD42024541879.

Antibiotics improve reproductive outcomes after frozen-thaw embryo transfer for chronic endometritis treatment, especially in those with repeated implantation failure

PURPOSE

To investigate the impact of antibiotic treatment for chronic endometritis (CE) on the pregnancy outcome of frozen-thawed embryo transfer (FET) cycles and the relevant clinical risk factors associated with CE.

METHODS

A retrospective cohort analysis was conducted on 1352 patients who underwent hysteroscopy and diagnostic curettage at Nanjing Maternal and Child Health Hospital from July 2020 to December 2021. All patients underwent CD138 immunohistochemical (IHC) testing to diagnose CE, and a subset of them underwent FET after hysteroscopy. Patient histories were collected, and reproductive prognosis was followed up.

RESULTS

Out of 1088 patients, 443 (40.7%) were diagnosed with CE. Univariate and multivariate binary logistic regression analyses revealed that parity ≥ 2, a history of ectopic pregnancy, moderate-to-severe dysmenorrhea, hydrosalpinx, endometrial polyps, a history of ≥ 2 uterine operations, and RIF were significantly associated with an elevated risk of CE (P < 0.05). Analysis of the effect of CE on pregnancy outcomes in FET cycles after antibiotic treatment indicated that treated CE patients exhibited a significantly lower miscarriage rate (8.7%) and early miscarriage rate (2.9%) than untreated non-CE patients (20.2%, 16.8%). Moreover, the singleton live birth rate (45.5%) was significantly higher in treated CE patients than in untreated non-CE patients (32.7%). Survival analysis revealed a statistically significant difference in the first clinical pregnancy time between treated CE and untreated non-CE patients after hysteroscopy (P = 0.0019). Stratified analysis based on the presence of recurrent implantation failure (RIF) demonstrated that in the RIF group, treated CE patients were more likely to achieve clinical pregnancy than untreated non-CE patients (P = 0.0021). Among hysteroscopy-positive patients, no significant difference was noted in pregnancy outcomes between the treatment and control groups (P > 0.05).

CONCLUSION

Infertile patients with a history of parity ≥ 2, hydrosalpinx, a history of ectopic pregnancy, moderate-to-severe dysmenorrhea, endometrial polyps, a history of ≥ 2 uterine operations, and RIF are at an increased risk of CE; these patients should be recommended to undergo hysteroscopy combined with CD138 examination before embryo transfer. Antibiotic treatment can improve the reproductive outcomes of FET in patients with CE, especially those with RIF.

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.

The Impacts of Inflammatory and Autoimmune Conditions on the Endometrium and Reproductive Outcomes

Background: A healthy pregnancy begins with an adequate endometrial state, even before the arrival of a blastocyst. Proper endometrial priming and the development of a tolerogenic decidua are key steps in creating the perfect environment for implantation and pregnancy. In these processes, the involvement of the maternal immune system seems to be of great relevance, modulating the different decidual immune populations to prepare the endometrium for a potential pregnancy. However, certain local pathologies of an inflammatory and autoimmune nature appear to have a direct impact on these phenomena, thus altering patients' reproductive outcomes. Methods: This literature review analyzes original articles, reviews, systematic reviews, and meta-analyses published between 1990 and 2024, concerning the impact of different inflammatory and autoimmune conditions on endometrial status and fertility. The included papers were obtained from Medline (Pubmed) and the Cochrane library. Results: There is evidence that endometriosis, adenomyosis, and chronic endometritis, through the promotion of a chronic inflammatory environment, are capable of altering endometrial immune populations, and, thus, processes essential for early pregnancy. Among other effects, these conditions have been linked to impaired decidualization, alterations in progesterone responsiveness, and hindered placentation. Similarly, antiphospholipid syndrome (APS), thyroid dysfunction, diabetes, and other pathologies related to glucose and gluten metabolism, due to their autoimmune nature, also appear to have a local impact on the uterine environment, affecting reproductive success through different mechanisms, including altered hormonal response and, again, impaired decidualization. Conclusions: The management of inflammatory and autoimmune diseases in assisted reproduction patients is gaining importance due to their direct impact on the endometrium. It is necessary to follow current expert recommendations and established therapeutic approaches in order to improve patients' prospects, ranging from antibiotic treatment in chronic endometritis to heparin and aspirin in APS, as well as hormonal treatments for endometriosis/adenomyosis or a gluten-free diet in celiac disease. All of them and the rest of the therapeutic perspectives, both current and under investigation, are presented throughout this work, assessing the possible improvements for reproductive outcomes.

Prevalence and confounders of chronic endometritis diagnosed using CD138 in patients with recurrent implantation failure

OBJECTIVE

This retrospective study aimed to investigate the prevalence of chronic endometritis, diagnosed using CD138 immunohistochemistry, among infertile women and to assess the association between chronic endometritis and recurrent implantation failure (RIF).

METHODS

In total, 266 patients who underwent hysteroscopy due to infertility between 2019 and 2020 were included in the analysis. Of these, 136 patients with RIF and 130 non-RIF patients were included in the study. CD138 immunohistochemistry test results, blood biomarkers (including natural killer cells, white blood cells, and the lymphocyte-to-neutrophil ratio), and data on pregnancy outcomes were obtained. If the CD138 test yielded a positive result, the patients received antibiotic treatment.

RESULTS

The overall proportion of CD138-positive patients was 32.7% (87/266). The CD138 positivity rate was not related to the number of cycles with implantation failure. In the RIF patient group, no significant associations were found between CD138 positivity and peripheral blood markers. The clinical pregnancy rates were similar between infertile women treated with antibiotics for chronic endometritis and those without chronic endometritis.

CONCLUSION

To improve the pregnancy rate in infertile patients, it may be helpful to combine CD138 testing with other laboratory tests and administer antibiotic treatment if the result is positive.

Endometrial preparation protocols did not impact pregnancy outcomes of patients with cured chronic endometritis

RESEARCH QUESTION

Do endometrial preparation protocols have an effect on pregnancy outcomes in patients with cured chronic endometritis?

DESIGN

A retrospective study was conducted on 3721 infertile patients from December 2018 to August 2020. Endometrial tissues obtained during the proliferative phase were immunostained for CD138. The presence of CD138-positive cells within the stromal cells indicated chronic endometritis. All patients diagnosed with chronic endometritis received oral antibiotics. Patients underwent endometrial preparation and frozen embryo transfer once chronic endometritis was cured. This study compared various endometrial preparation protocols to assess their effects on pregnancy outcomes. Additionally, it aimed to investigate differences in pregnancy outcomes between patients without chronic endometritis and patients with cured chronic endometritis while following the same endometrial preparation protocol.

RESULTS

Almost no differences in pregnancy outcomes were observed between natural cycle, hormone replacement therapy (HRT) and gonadotrophin-releasing hormone agonist-HRT (GnRH agonist-HRT) protocols in patients without chronic endometritis and patients with cured chronic endometritis. The only notable difference was that, among women without chronic endometritis, the early miscarriage rate was higher for the GnRH agonist-HRT protocol (25.8%) compared with the natural cycle (17.4%) and HRT (17.7%) protocols (P = 0.025). However, this difference was not significant after adjusting for confounders (adjusted OR 1.383, 95% CI 0.931-2.055). The live birth rate, clinical pregnancy rate, early miscarriage rate, ectopic pregnancy rate and ongoing pregnancy rate did not differ significantly (P > 0.05) between patients without chronic endometritis and patients with cured chronic endometritis who underwent natural cycle, HRT and GnRH agonist-HRT protocols.

CONCLUSION

Endometrial preparation protocols had no impact on pregnancy outcomes in patients with cured chronic endometritis.

Bibliometric analysis of the global trends in immune-related recurrent pregnancy loss research over the last two decades

PROBLEM

A comprehensive analysis was conducted to explore the scientific output on immune-related recurrent pregnancy loss (RPL) and its key aspects. Despite the lack of clear explanations for most RPL cases, immune factors were found to play a significant role.

METHOD OF STUDY

The study utilized a bibliometric approach, searching the Web of Science Core Collection database for relevant literature published between 2004 and 2023.

RESULTS

The collected dataset consisted of 2228 articles and reviews, revealing a consistent increase in publications and citations over the past two decades. The analysis identified the United States and China as the most productive countries in terms of RPL research. Among the institutions, Fudan University in China emerged as the top contributor, followed by Shanghai Jiaotong University. Kwak-kim J was the most prolific author, while Christiansen Ob had the highest number of co-citations. The top 25 co-cited references on diagnosis, treatment, and mechanisms formed the foundation of knowledge in this field. By examining keyword co-occurrence and co-citations, the study found that antiphospholipid syndrome and natural killer cells were the primary areas of focus in immune-related RPL research. Additionally, three emerging hotspots were identified: chronic endometritis, inflammation, and decidual macrophages. These aspects demonstrated increasing interest and research activity within the field of immune-related RPL.

CONCLUSIONS

Overall, this comprehensive bibliometric analysis provided valuable insights into the patterns, frontiers, and focal points of global scientific output related to immune-related RPL.

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.

Cyclical endometrial repair and regeneration: Molecular mechanisms, diseases, and therapeutic interventions

The endometrium is a unique human tissue with an extraordinary ability to undergo a hormone-regulated cycle encompassing shedding, bleeding, scarless repair, and regeneration throughout the female reproductive cycle. The cyclical repair and regeneration of the endometrium manifest as changes in endometrial epithelialization, glandular regeneration, and vascularization. The mechanisms encompass inflammation, coagulation, and fibrinolytic system balance. However, specific conditions such as endometriosis or TCRA treatment can disrupt the process of cyclical endometrial repair and regeneration. There is uncertainty about traditional clinical treatments' efficacy and side effects, and finding new therapeutic interventions is essential. Researchers have made substantial progress in the perspective of regenerative medicine toward maintaining cyclical endometrial repair and regeneration in recent years. Such progress encompasses the integration of biomaterials, tissue-engineered scaffolds, stem cell therapies, and 3D printing. This review analyzes the mechanisms, diseases, and interventions associated with cyclical endometrial repair and regeneration. The review discusses the advantages and disadvantages of the regenerative interventions currently employed in clinical practice. Additionally, it highlights the significant advantages of regenerative medicine in this domain. Finally, we review stem cells and biologics among the available interventions in regenerative medicine, providing insights into future therapeutic strategies.

Activation of SGK1/ENaC Signaling Pathway Improves the Level of Decidualization in Unexplained Recurrent Spontaneous Abortion

Recurrent spontaneous abortion (RSA) is one of the most common complications during pregnancy and seriously affects women's physical and mental health. About 50% of RSA cases are of unknown etiology. Our previous study found that the decidual tissue of patients with unexplained recurrent spontaneous abortion (URSA) had low expression levels of serum and glucocorticoid-induced protein kinase (SGK) 1. Endometrial decidualization is a key link in the early stage of pregnancy and is crucial to the development and maintenance of pregnancy. Decidualization is the proliferation and differentiation of endometrial stromal cells into deciduals, which involves a complex physiological process such as ovarian steroid hormones (estrogen, progesterone, prolactin, etc.), growth factors, and intercellular signaling. The binding of estrogen and its receptor stimulates the synthesis of endometrial deciduating markers prolactin (PRL) and insulin-like growth factor binding protein 1 (IGFBP-1), which mediates the occurrence of decidualization. Among them, SGK1/ENaC is a signaling pathway closely related to decidualization. The purpose of this study was to further investigate the expression of SGK1 and decidualization-related molecules in the decidual tissue of URSA patients and to explore the potential mechanism of SGK1's protective effect in URSA patients and in mouse models. Decidual tissue samples from 30 URSA patients and 30 women who actively terminated pregnancy were collected, and a URSA mouse model was established and treated with dydrogesterone. Expression levels of SGK1 and its signaling pathway-related proteins (p-Nedd4-2, 14-3-3 protein and ENaC-a), estrogen and progesterone receptors (ERβ, PR), and decidualization markers (PRLR, IGFBP-1) were assessed. Our study found that SGK1, p-Nedd4-2, 14-3-3 proteins, and ENaC-a expression levels were reduced in the decidual tissue, the SGK1/ENaC signaling pathway was inhibited, and the expression levels of the decidualization markers PRLR and IGFBP-1 were downregulated in the URSA group compared with the controls. Additionally, the concentrations of E2, P, and PRL in the serum of mice were decreased in the URSA group compared with the controls. However, SGK1/ENaC pathway-related proteins, estrogen and progesterone and their receptors, and decidualization-related molecules were upregulated by dydrogesterone. These data suggest that estrogen and progesterone can induce decidualization by activating the SGK1/ENaC signaling pathway; disruption of this pathway can lead to the development of URSA. Dydrogesterone can increase the expression level of SGK1 protein in decidual tissue.

Chronic endometritis: screening, treatment, and pregnancy outcomes in an academic fertility center

PURPOSE

To identify the prevalence of chronic endometritis (CE), compare the efficacy of antibiotic regimens for CE, and examine pregnancy outcomes after treatment for CE among patients in an academic fertility clinic.

METHODS

In this retrospective cohort study, data from patients who underwent endometrial sampling (ES) for CE evaluation at a single academic institution from 2014 to 2020 were collected and analyzed. Rates of CE were compared by indication for ES including recurrent pregnancy loss (RPL), implantation failure (IF), and recent first-trimester pregnancy loss. Treatment and pregnancy outcomes were also evaluated.

RESULTS

Six hundred fifty-three individuals underwent ES to evaluate for CE. The overall prevalence of CE was 28.5%; when stratified by indication, the prevalence of CE was 66.2% for recent first-trimester loss, 27.9% for RPL, and 13.1% for IF (p < .001). Of those with CE, 91.9% received antibiotics, most commonly doxycycline (76.0%). CE clearance was not significantly different when doxycycline was compared to all other regimens (71.3% vs. 58.8%, p = .17), and 68.5% of patients cleared CE after one course of antibiotics. Following two antibiotic courses, CE was cleared in 88.3% of patients. Live birth rates (LBRs) were higher for those with cleared CE compared to patients with untreated CE (34.1% vs. 5.6%, p = .014) and similar for those with cleared CE versus those without CE (34.1% vs. 29.3%, p = .297).

CONCLUSION

CE is common among patients with infertility, particularly those with a recent first-trimester loss. Treatment and clearance of CE were associated with higher LBRs; however, persistent CE was common despite treatment with antibiotics.

Impact of antibiotic cured chronic endometritis on perinatal outcomes: Re-evaluation of a cohort study with a detailed follow-up

PROBLEM

The impact of antibiotic-cured chronic endometritis (CE) on perinatal outcomes of patients conceived with frozen embryo transfer (FET) was unclear.

METHOD

This study was to re-evaluate the perinatal outcomes of a cohort of infertile patients who had undergone endometrial biopsy for CE detection from February 2018 to December 2019 and successfully delivered babies after FET. The study population was divided into two groups: the non-CE (NCE) group (0-4/HPF CD138) and the cured-CE (CCE) group (CD138+/HPF≥5 and has been cured after one or two rounds of antibiotic treatment). For subgroup analysis, the NCE group was further divided into subgroup 1 (CD138+/HPF = 0), subgroup 2 (CD138+/HPF = 1-4 with antibiotic treatment), and subgroup 3 (CD138+/HPF = 1-4 without antibiotic treatment) RESULTS: A total of 321 live births, including 210 in the NCE group and 111 in the CCE group were analyzed. The prevalence rates of premature rupture of the membrane and preterm birth were comparable between NCE and CCE (6.2% vs. 7.1% and 10.8% vs. 10.1%, respectively) groups. In addition, no differences were detected in the rates of placenta-mediated complications, such as preeclampsia, placenta abruption, or low birthweight. Multiple logistic analyses confirmed that CCE was not associated with an increased risk of any adverse perinatal outcomes. Subgroup analysis in NCE failed to find any significant differences in the incidences of obstetrical and neonatal complications.

CONCLUSIONS

CCE might not increase the risks of adverse perinatal outcomes after antibiotic treatment.

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.

Chronic poor healing wounds of post cesarean scar diverticulum: Altered angiogenesis and immunobiology

Cesarean section (CS) scar diverticula (CSD) is an important cause impede further fecundity, with rather complicated pathophysiologic mechanisms and unclear etiopathogenesis. In this study, we detect the influences of CSD on the pregnancy outcomes in in-vitro fertilization (IVF) or intra-cytoplasmic sperm injection (ICSI) embryo transfer (ET) cycles, and further explore the mechanisms involved based on histopathology and immunology differences in endometrium between CSD and vaginal birth (VB) women. The CS group had significantly lower CLBR compared to NCS group. Histopathological analysis showed that the higher prevalent of CE is accompanied by excessive fibroblast proliferation at the lower segment of uterus and significantly exaggerated vascular proliferation in situ. Intrauterine inflammatory cytokines including IL-1α, IL-1β, IL-6, IL-8, TNF-α and SDF-1α were also increased in CSD group. The present data suggests impaired fecundity in CSD women undergoing IVF/ICSI treatment. Although the causal relationship is ambiguous, the potential mechanisms may involve persistent inflammatory response in the uterine cavity, active vascular proliferation accompanied with increased fibrosis which are responsible for poor chronic wound healing of CSD.

Precision Medicine for Chronic Endometritis: Computer-Aided Diagnosis Using Deep Learning Model

Chronic endometritis (CE) is a localized mucosal infectious and inflammatory disorder marked by infiltration of CD138(+) endometrial stromal plasmacytes (ESPC). CE is drawing interest in the field of reproductive medicine because of its association with female infertility of unknown etiology, endometriosis, repeated implantation failure, recurrent pregnancy loss, and multiple maternal/newborn complications. The diagnosis of CE has long relied on somewhat painful endometrial biopsy and histopathologic examinations combined with immunohistochemistry for CD138 (IHC-CD138). With IHC-CD138 only, CE may be potentially over-diagnosed by misidentification of endometrial epithelial cells, which constitutively express CD138, as ESPCs. Fluid hysteroscopy is emerging as an alternative, less-invasive diagnostic tool that can visualize the whole uterine cavity in real-time and enables the detection of several unique mucosal findings associated with CE. The biases in the hysteroscopic diagnosis of CE; however, are the inter-observer and intra-observer disagreements on the interpretation of the endoscopic findings. Additionally, due to the variances in the study designs and adopted diagnostic criteria, there exists some dissociation in the histopathologic and hysteroscopic diagnosis of CE among researchers. To address these questions, novel dual immunohistochemistry for CD138 and another plasmacyte marker multiple myeloma oncogene 1 are currently being tested. Furthermore, computer-aided diagnosis using a deep learning model is being developed for more accurate detection of ESPCs. These approaches have the potential to contribute to the reduction in human errors and biases, the improvement of the diagnostic performance of CE, and the establishment of unified diagnostic criteria and standardized clinical guidelines for the disease.

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.

Chronic endometritis increases the recurrence of endometrial polyps in premenopausal women after hysteroscopic polypectomy

BACKGROUND

The reported recurrence rate of endometrial polyps (EPs) after hysteroscopic polypectomy varied widely, and the factors influencing the recurrence of EPs are still controversial. Furthermore, the known definite independent risk factors are almost unchangeable, such as the number of EPs and previous polypectomy history. The aim of this study was to evaluate the impact of chronic endometritis (CE) on the recurrence of EPs in premenopausal women who underwent hysteroscopic polypectomy.

METHODS

A retrospective study was conducted at a university-affiliated hospital. Premenopausal women who underwent hysteroscopic polypectomy were enrolled, and those with definite confounding factors for polyp recurrence were excluded, including endometriosis and previous polypectomy history. A total of 233 women were enrolled in this study, including 64 (27.5%) cases with CE and 169 (72.5%) cases without CE. CE was diagnosed via immunohistochemical detection of CD138 on the endometrial specimen. Comparison of the recurrence rate of EPs was performed in women with or without CE at each monitoring stage (i.e., at 3, 6, 9 and 12 months) after hysteroscopic polypectomy.

RESULTS

The recurrence rates of EPs at one year in patients with and without CE were 26.6% (95% confidence interval [CI] 15.8-37.4%) and 9.5% (95% CI 5.0-14.0%), respectively, with an overall recurrence rate of 14.2% (95% CI 9.7-18.7%). The hazard ratio (HR) for EPs recurrence in the EPs with CE cohort versus the EPs without CE cohort was 3.08 (95% CI 1.56-6.09) (P = 0.001). Similarly, the recurrence rate of EPs was significantly higher in women with CE than in those without CE at each monitoring stage (i.e., 3, 6 and 9 months). CE and multiple EPs were risk factors for EPs recurrence. The HR for EPs recurrence in the EPs with CE cohort compared with the EPs without CE cohort was 3.06, after adjustment for the number of EPs.

CONCLUSIONS

CE was a harmful factor for the recurrence of EPs in premenopausal women after hysteroscopic polypectomy. Thus, routine screening for CE during hysteroscopic polypectomy was needed. Frequent monitoring was needed for multiple EPs as the number of EPs also contributed to polyp recurrence.

Analysis of pregnancy outcomes in patients with recurrent implantation failure complicated with chronic endometritis

Chronic endometritis (CE) has been considered to reduce uterine receptivity and negatively affect reproductive outcomes for in vitro fertilization-embryo transfer (IVF-ET) patients, especially for people undergoing recurrent implantation failure (RIF). To investigate the effects of antibiotic and platelet-rich plasma (PRP) therapy on pregnancy outcomes following frozen-thawed embryo transfer (FET) in RIF patients with CE, endometrial specimens of 327 patients with RIF obtained by endometrial scratching during mid-luteal phase were immunostained by multiple myeloma oncogene-1 (Mum-1)/syndecan-1 (CD138). RIF patients with CE were given antibiotics and PRP treatment. According to the Mum-1⁺/CD138⁺ plasmacytes after treatment, patients were divided into persistent weak positive CE (+) group, CE (-) group and non-CE group. FET was performed and the basic characteristics and pregnancy outcomes of patients in three groups were compared. Among 327 RIF patients, 117 patients were complicated with CE, the prevalence was 35.78%. The prevalence of strong positive was 27.22% and that of weak positive was 8.56%. 70.94% patients with CE converted to negative after treatment. There was no significant difference in the basic characteristics, including age, BMI, AMH, AFC, infertility years, infertility types, number of previous transplant cycles, endometrial thickness on transplantation day and number of transplanted embryos (p > 0.05); The positive rate of hCG, clinical pregnancy rate and implantation rate in CE (-) group were significantly increased compared with the weak CE (+) group and non-CE group (p < .01), and the live birth rate also improved (p < .05). Whereas, the rate of early abortion in CE (-) group was 12.70%, which was higher than that in weak CE (+) group and non-CE group (p < .05). After multivariate analysis, number of previous failed cycles and CE remained independent factors associated with live birth rate, while only CE remained to be the independent factor of clinical pregnancy rate. It is recommended to perform CE-related examination for patients with RIF. Antibiotic and PRP treatment can significantly improve pregnancy outcomes of patients with CE negative conversion in FET cycle.

The Cystic Anechoic Zone of Uterine Cavity Newly Observed during Controlled Ovarian Hyperstimulation Affects Pregnancy Outcomes of Fresh Embryo Transfer

During controlled ovarian hyperstimulation (COH), cystic anechoic zones in the uterine cavity are occasionally visible. This retrospective matched cohort study collected information on patients who underwent in vitro fertilization/intracytoplasmic injection (IVF/ICSI) from January 2014 to December 2020 at our center. The propensity score algorithm matched 179 cases that had uterine cystic anechoic zones, with 358 which did not have uterine cystic anechoic zones cases. After matching, the live birth rate (38.0% vs. 48.6%, p = 0.025) of patients with uterine cystic anechoic zones was lower than that in the no uterine cystic anechoic zone group, while for clinical pregnancy miscarriage rate (22.2% vs. 12.4%, p = 0.031), the rate was higher. The results showed no correlation in the association between live birth rate (r = −0.027, p = 0.718), clinical pregnancy rate (r = −0.037, p = 0.620) or biochemical pregnancy rate (r = −0.015, p = 0.840) and the diameters of the cystic anechoic zones in the uterine cavity. There was a significant difference in the type of endometrium between the two groups (p < 0.001). The result of this study can provide guidance to patients on whether to undergo fresh embryo transfer in the current cycle.

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.

Bovine lactoferrin suppresses inflammatory cytokine expression in endometrial stromal cells in chronic endometritis

Chronic endometritis (CE) is a type of chronic inflammation in the endometrium that is associated with infertility, which is primarily due to implantation failure. Antibiotics are the most common treatment for CE. However, some patients with CE are resistant to antibiotic treatment, while others refuse this treatment. Therefore, we focused on lactoferrin (Lf), which exhibits antimicrobial and anti-inflammatory properties, and studied its effect on inflammation in endometrial stromal cells (ESCs) from patients with CE. Endometrial tissue was collected from patients with CE, and ESCs were isolated and cultured. When ESCs were cultured with bovine lactoferrin (bLf: 1 mg/mL), the mRNA expression of TNF-α (p < 0.05) and IL-1β (p < 0.01) was significantly decreased compared with that in cells cultured without bLf. The level of TNF-α protein in the culture medium was significantly decreased (p < 0.01), while that of IL-1β was also decreased, but not significantly (p < 0.10), when 1 mg/mL of bLf was added to the culture medium. When more inflammation was induced artificially by adding 0.1 ng/mL of TNF-αto ESCs, the addition of bLf (1 mg/mL) to ESCs decreased IL-6 and IL-1β mRNA expression to levels similar to those in ESCs without TNF-α treatment. Furthermore, it was revealed that the actions of bLf are mediated by the AKT and MAPK intracellular signaling pathways, which are mechanisms by which the increase in TNF-α-induced cytokine expression is suppressed in ESCs. bLf suppresses the expression of inflammatory cytokines in human ESCs and may be a new therapeutic candidate for CE.

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).

Challenges in Clinical Diagnosis and Management of Chronic Endometritis

Chronic endometritis (CE) is a local mucosal infectious and inflammatory disorder characterized by unusual filtration of CD138(+) endometrial stromal plasmacytes. CE is attracting attention due to its potential association with infertility of unknown etiology, repeated implantation failure, recurrent pregnancy loss, and several maternal/neonatal complications. Due to the variance in study design among researchers, universal diagnostic criteria remain to be established for the clinical diagnosis and management of CE. This review article aims to summarize current knowledge and provide insights into unsolved questions on CE to establish clinical guidelines for the disease from the viewpoint of human reproduction.

Additional dydrogesterone for the treatment of chronic endometritis treated with antibiotic in premenopausal women with endometrial polyps: a retrospective cohort study

Background

To assess the efficacy of dysdrogesterone in the treatment of chronic endometritis (CE) treated with antibiotic in premenopausal women with endometrial polyps (EPs).

Methods

Routine detection of endometrium was simultaneously conducted to determine whether there was CE by syndecan-1 (CD138), while women underwent hysteroscopic polypectomy in our hospital. Antibiotic was given for the treatment of CE. A total of 235 premenopausal women with CE who underwent hysteroscopic polypectomy were enrolled in the retrospective observational study. In the control group, single antibiotic was given for the treatment of CE form January 2016 to December 2018, and in the treatment group additional dydrogesterone was used from January 2019 to November 2020. Comparison of cure rates of CE with different treatment regimens was performed.

Results

The cure rates of CE in dydrogesterone and antibiotic combination group and the single antibiotic group were 85.2% and 74.3%, respectively, with overall cure rate of 80.0% (188/235). The combination group showed better effects regarding the cure rate of CE (P < .05). Multivariate analysis confirmed that the cure rate of CE was not affected by age, body mass index, number of EPs, the status of estrogen receptor and the status of progesterone receptor. Conversely, dydrogesterone and endometrial scratching were beneficial factors for cure rate increase with antibiotic treatment.

Conclusion

Combination of dydrogesterone and antibiotic was more effective for cure rate of CE than antibiotic alone in premenopausal women after hysteroscopic polypectomy. Endometrial scratching also contributed to the cure rate increase with antibiotic treatment.

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.

The Continuum of Microbial Ecosystems along the Female Reproductive Tract: Implications for Health and Fertility

The microbial ecosystem of the female urogenital tract is composed of many niche microenvironments across multiple organ systems in the urinary and reproductive tract. It is complex and contains a variety of bacteria, archaea, viruses, yeast, and protozoa-Many of which are still unidentified or whose functionality is unknown. Unlike the gut microbiome, whose composition is relatively stable in the absence of external perturbations, the urogenital microbiome is constantly shifting in response to biological cycles such as hormonal fluctuations during menstruation. Microbial composition differs between women but the dominance of some microbial families, such as Lactobacillaceae and other lactic acid-producing bacteria, are shared. Research suggests that it is difficult to define a universal healthy urogenital microbiome and consequently map a path to recovery from disease due to dysbiosis. Due to its temporal shifts, the female urogenital microbiome offers a unique opportunity to examine the biological mechanisms that work to restore a microbiome to its baseline. Common functional disorders in women's health are often difficult to diagnose and treat, are prone to recurrence, and can lead to subfertility or infertility. Knowledge of the interconnected microorganism communities along the continuum of the female reproductive tract could revolutionize the quality of women's healthcare.

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.

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.

Lincomycin Administration against Persistent Multi-Drug Resistant Chronic Endometritis in Infertile Women with a History of Repeated Implantation Failure

Chronic endometritis (CE) is an infectious disease of the uterine lining, which is characterized by endometrial stromal plasmacyte (ESPC) infiltration. CE is often seen in infertile women with a history of repeated implantation failure (RIF) following an in vitro fertilization-embryo transfer program, recurrent pregnancy loss, and unknown etiology. Oral antibiotic agents, such as doxycycline, metronidazole, ciprofloxacin, azithromycin, and moxifloxacin, have been prescribed and are effective in the treatment of CE. Multi-drug resistance (MDR), however, is an emerging issue, as in other medical fields. We report six cases of persistent MDR-CE in infertile women who were resistant to all the aforementioned antibiotic agents. The bacterial genera and microbial communities unique to persistent MDR-CE were not identified in their vaginal secretions and/or endometrial fluid. Oral lincomycin administration (14 days, 1500 mg/day) was effective in the eradication of ESPCs in these women. In the embryo transfer cycles following histopathologic confirmation of cure (elimination of ESPCs) of persistent MDR-CE, three out of them had a successful live birth.

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.

Multi-drug-resistant chronic endometritis in infertile women with repeated implantation failure: trend over the decade and pilot study for third-line oral antibiotic treatment

PURPOSE

To evaluate the yearly prevalence and annual transition of multi-drug-resistant-chronic endometritis (MDR-CE) in infertile women with a history of repeated implantation failure (RIF) and to establish the third-line antibiotic treatment regimen against MDR-CE.

METHODS

This retrospective/prospective cohort and pilot study included 3473 RIF women between April 2010 and September 2021. The endometrial stromal plasmacyte density index (ESPDI) was calculated in 3449 CD138-immunostained endometrial sections to evaluate CE. The microbiota in the vaginal secretions and endometrial fluid was compared between 17 patients with MDR-CE and 16 patients with antibiotics-sensitive CE. In a pilot study, oral moxifloxacin (400 mg/day, 10 days, n = 24) or azithromycin (500 mg/day, 3 days, n = 24) was administered to eligible patients with MDR-CE.

RESULTS

From April 2010 to March 2020, CE was detected in 31.4% of RIF women and MDR was detected in 7.8% of CE. While the prevalence of CE was stable for a decade, MDR in CE increased steadily (OR 8.27, 95% CI 2.58-26.43, p trend < 0.001). The bacterial species/communities unique to MDR-CE were not found. The histopathologic cure rate of MDR-CE was similar between the moxifloxacin and azithromycin groups (79.2% vs 75.0%, OR 1.27, 95% CI 0.32-4.89, p value 0.73), as well as reproductive outcomes in subsequent embryo transfer cycles.

CONCLUSION

In RIF women, MDR in CE increased over the decade. As a third-line treatment for MDR-CE, azithromycin may have a clinical advantage due to its shorter time administration periods.

CLINICAL TRIAL NUMBER

ClinicalTrials.gov Identifier: UMIN-CTR 000029449/000031909.

Does antibiotic therapy for chronic endometritis improve clinical outcomes of patients with recurrent implantation failure in subsequent IVF cycles? A systematic review and meta-analysis

PURPOSE

This study aims to assess whether antibiotic therapy for chronic endometritis (CE) could improve subsequent IVF outcomes in patients with recurrent implantation failure (RIF).

METHODS

Studies that explore CE treatment in patients with RIF were retrieved from PubMed, EMBASE, Wanfang, and Google Scholar up to Jan 31, 2022. All retrieved studies were selected according to the inclusion and exclusion criteria. The main outcome measures include implantation rate (IR), clinical pregnancy rate (CPR), ongoing pregnancy rate/live birth rate (OPR/LBR), and miscarriage rate (MR). Odds ratios (ORs) were analyzed for pregnancy outcomes with a 95% confidence interval (CI).

RESULTS

Nine articles were enrolled in this study. Patients receiving oral antibiotic administration (OAA) did not show any advantage over patients without CE with regard to IR, OPR/LBR, and MR, but they showed a higher CPR. Patients with cured CE after OAA therapy had significantly higher CPR, IR, and OPR/LBR compared with patients without CE. Patients with persistent CE after OAA therapy had significantly lower IR, CPR, and OPR/LBR compared with patients without CE. Patients with cured CE had significantly higher IR, CPR, and OPR/LBR compared with persistent CE patients.

CONCLUSIONS

Antibiotic treatment may improve the pregnancy outcomes of RIF patients in subsequent IVF cycles only if the condition of CE is confirmed cured in a control biopsy afterwards. Otherwise, no sufficient evidence has shown improvements in clinical outcomes in RIF patients with persistent CE.

An Altered Microbiota in the Lower and Upper Female Reproductive Tract of Women with Recurrent Spontaneous Abortion

Recurrent spontaneous abortion (RSA) is a complex multifactorial disease. Recently, the microbiota of the female reproductive tract, as an emerging factor in RSA, has gradually attracted the attention of many clinical researchers. Here, we reported that the microbiota of the lower and upper female reproductive tracts from patients with RSA showed no significant differences in alpha diversity compared to that of controls. Beta diversity was significantly higher in the RSA group than in the control group in the vaginal microbiota (P = 0.036), cervical microbiota (P = 0.010) and microbiota from uterine lavage fluid (P = 0.001). In addition, dramatic decreases in gamma interferon and interleukin-6 cytokine levels were observed in the RSA group. In conclusion, our data suggested altered microbial biodiversity in the vagina, cervix and uterine lavage fluid in the RSA group. Alterations in the microbiota in the uterine cavity could be associated with altered cytokine levels, which might be a risk factor for RSA pathogenesis. Moreover, the microbiota composition differed markedly from the lower genital tract to the uterine cavity, and the microbiota in the uterine cavity also distinctly varied between endometrial tissue and uterine lavage fluid in the RSA group. Hence, sampling with these two methods simultaneously allowed a more comprehensive perspective of microbial colonization in the uterine cavity. IMPORTANCE As an obstacle to pregnancy, recurrent spontaneous abortion (RSA) can be caused by a variety of factors, and a current understanding of the etiology of RSA is still lacking; half of cases have an unknown cause. A substantial fraction of patients show no improvement after treatment. Since the microbiota of the female reproductive tract has been proposed as an emerging factor in RSA patients, further investigation is needed to provide guidance for clinical therapy. In general, this is the first report describing the distinct alterations of the vaginal, cervical, and uterine microbiota in RSA, not just that in the vagina. Furthermore, another major strength of this study derived from the further in-depth investigation and analysis of the characteristics of the microbiota colonizing the upper female genital tract in RSA, which provided a more comprehensive view for investigating the uterine microbiota.

Risk of spontaneous abortion after antibiotic therapy for chronic endometritis before in vitro fertilization and intracytoplasmic sperm injection stimulation

OBJECTIVE

To investigate whether cured chronic endometritis (CE) from antibiotic treatment would be associated with a higher risk of spontaneous abortion in the following in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) treatment.

DESIGN

Prospective cohort study.

SETTING

Tertiary reproductive medicine center.

PATIENT(S)

Patients with infertility who underwent a routine hysteroscopy underwent an IVF/ICSI stimulation between January 1, 2019, and December 31, 2020. Women with CE (N = 338) underwent antibiotic therapy, and the assisted reproductive outcomes were then compared with women without CE (N = 7,962).

INTERVENTION(S)

Chronic endometritis was diagnosed through hysteroscopy and confirmed by histology and immunohistochemistry for CD138.

MAIN OUTCOME MEASURE(S)

Spontaneous abortion rate after the initial embryo transfer.

RESULT(S)

A total of 7,218 patients underwent embryo transfer, with 330 in the cured CE group and 6,888 in the non-CE group. Women with cured CE had a higher rate of spontaneous abortion than did those without CE (11.8% vs. 9.2%; crude odds ratio [OR], 1.32 [0.94, 1.86]), and this difference was statistically significant after adjusting for confounding variables (adjusted OR, 1.49 [1.01, 2.19]). The live birth rate was 43.9% in the cured CE group and 50.5% in the non-CE group (crude OR, 0.77 [0.62, 0.96]; adjusted OR, 0.73 [0.59, 0.92]). The incidence of clinical pregnancy did not differ significantly between the 2 groups (56.1% vs. 60.0%; crude OR, 0.85 [0.68, 1.06]; adjusted OR, 0.83 [0.66, 1.03]). Sensitivity analyses stratified by initial fresh- or frozen-thawed embryo transfer cycles resulted in similar results.

CONCLUSION(S)

Chronic endometritis cured with antibiotic therapy was associated with an increased risk of spontaneous abortion among women undergoing IVF/ICSI treatment. The interpretation of the findings is limited by a potential confounding bias.

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.

Endometrial polyp is associated with a higher prevalence of chronic endometritis in infertile women

OBJECTIVE

To assess the prevalence of chronic endometritis (CE) among infertile women with endometrial polyps (EP).

METHODS

From June 2017 to October 2021, 583 patients in the polyp group (group A-group A1: single-polyp group, 322 patients; group A2: multiple-polyp group, 261 patients) and 4534 patients in the non-polyp group (group B) were included in this retrospective study. Hysteroscopic polypectomy was performed in group A. Endometrial biopsy and CD138 immunohistochemistry staining for specimens was carried out in all groups.

RESULTS

Prevalence of CE was significantly higher in group A than in group B (45.28% vs. 27.94%, P < 0.001). A significantly higher prevalence of CE was found in group A1 and group A2 compared with group B (42.24% vs. 27.94%, P < 0.001; 49.04% vs. 27.94%, P < 0.001; respectively). No significant difference in the comparison of CE prevalence was found between group A1 and group A2. Similar results were achieved in the subgroup analysis among patients aged 40 years or older and patients younger than 40 years.

CONCLUSION

EP, either single EP or multiple EP, positively correlates with CE. The prevalence of CE was similar between the single-polyp group and the multiple-polyp group.

Differential Vaginal Microbiota Profiling in Lactic-Acid-Producing Bacteria between Infertile Women with and without Chronic Endometritis

Purpose: Chronic endometritis (CE) is an infectious and inflammatory disorder associated with infertility of unknown etiology, repeated implantation failure, and recurrent pregnancy loss. In the current clinical practice, intrauterine interventions such as endometrial biopsy/histopathologic examinations and/or hysteroscopy are required for the diagnosis of CE. In this study, we analyzed the microbiota in vaginal secretions (VS) as a potential prediction tool for CE in infertile women. Methods: Using next-generation sequencing analysis, we compared the VS and endometrial fluid (EF) microbiota in infertile women with (n = 20) or without CE (n = 103). Results: The detection rate of Streptococcus and Enterococcus as well as the bacterial abundance of Atopobium and Bifidobacterium in the VS microbiota was significantly lower in the CE group than in the non-CE group. Meanwhile, the detection rate and bacterial abundance of Lactobacillus in the EF and VS microbiota were at similar levels between the two groups. Conclusion: These findings suggest that VS microbiota in infertile women with CE is characterized by the reduction in Bifidobacterium and lactic-acid-producing bacteria other than Lactobacillus. Our results hold promise for the prediction of CE, not by somewhat interventional intrauterine procedures, but by less invasive VS sampling. TRIAL REGISTRATION NUMBER: UMIN000029449 (registration date 6 October 2017).

The Use of Probiotics for Management and Improvement of Reproductive Eubiosis and Function

Reproductive tract dysbiosis, due to the action of pathogens and/or unhealthy lifestyle, has been related to many reproductive diseases and disorders in mammalian species. Classically, such a problem has been confronted by the administration of antibiotics. Despite their effectiveness for controlling disease, treatments with antibiotics may negatively affect the fertility of males and females and, mainly, may induce antibiotic resistance. Accordingly, safer alternatives for maintaining reproductive system eubiosis, such as probiotics, are required. The present review summarizes the current knowledge on the biodiversity of the microbiota at the reproductive tract, possible changes in the case of dysbiosis, and their relationships with adequate reproductive health and functioning in both females and males. Afterwards, mechanisms of action and benefits of different probiotics are weighed since the biological activities of probiotics may provide a promising alternative to antibiotics for maintaining and restoring reproductive eubiosis and function. However, at present, it is still necessary for further research to focus on: (a) identifying mechanisms by which probiotics can affect reproductive processes; (b) the safety of probiotics to the host, specifically when consumed during sensitive reproductive windows such as pregnancy; and (c) the hazards instructions and regulatory rules required for marketing these biological-based therapies with sufficient safety. Thus, in this review, to draw a comprehensive overview with a relatively low number of clinical studies in this field, we showed the findings of studies performed either on human or animal models. This review strategy may help provide concrete facts on the eligible probiotic strains, probiotics colonization and transfer route, and prophylactic and/or therapeutic effects of different probiotic strains.

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.

The association between chronic endometritis and uterine fibroids

Background:

Some studies reported the association between fibroids with uterine inflammation. By considering this hypothesis, the formation and recurrence of uterine fibroids can be prevented by diagnosis and treatment of inflammation, and complications and costs can be reduced. This study aimed to evaluate the association between chronic endometritis and uterine fibroids in non-menopausal women.

Materials and Methods:

This prospective case-control study was performed on non-menopausal women referred to Al-Zahra Hospital in Rasht during April 2019-April 2020. Non- menopausal women of reproductive age (20-55 years old) with abnormal uterine bleeding who were candidates for hysteroscopy based on medical history and ultrasound reports were included in this study. The case group with fibroids were divided into two groups of intramural and subserosal myoma group and submucosal group based on the location of fibroids. The control group was patients with abnormal uterine bleeding complaints and no uterine fibroid. Endometrial specimens were examined by a pathologist for histological and immunochemistry assessments. In interpreting the results of endometrial biopsy, a positive result was indicated by the presence of one or more plasma cells per 10 high power field. Data were gathered by a form including age, parity, history of recurrent miscarriage, patient’s complaint (abnormal uterine bleeding), hysteroscopic results (submucosal myoma-polyp-normal), uterine histology (polyp, endometritis, and hyperplasia) and prevalence of chronic endometritis based on plasma cell in the biopsy. Data were analyzed by SPSS software version 21. Data were reported by descriptive statistics including number, percent, mean and standard deviation. The normality of quantitative data was assessed by the Kolmogorov- Smirnov test. Mann-Whitney U test, Chi-square and Fisher exact tests were used to compare groups and logistic regression was used to control the effect of confounders.

Results:

The incidence of chronic endometritis was 39% (38 out of 97) and a higher incidence of chronic endometritis was noted in the case group than the control group (46% vs. 31%), No significant difference was observed between the two groups (P > 0.05). However, the incidence of chronic endometritis in women with submucosal myoma was higher than the intramural and subserosal groups (64% vs. 37%) (P = 0.04). To control the effect of age on the rate of chronic endometritis in both groups, no significant effect was observed in logistic regression.

Conclusions:

The results showed the overall incidence of chronic endometritis was higher than previous studies and also the incidence was higher and more significant in women with submucosal myoma than in the intramural and subserosal group. As in this study, authors assessed the association between chronic endometritis and uterine fibroids, further studies assessing the cause and effect relationships are recommended.

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.

Overexpression of hypoxia-inducible factor 1α and excessive vascularization in the peri-implantation endometrium of infertile women with chronic endometritis

OBJECTIVE

Chronic endometritis (CE) contributes to impaired endometrial receptivity and is closely associated with poor in vitro fertilization (IVF) outcomes. However, the mechanisms underlying CE are unclear. Here, we investigated the role of the hypoxic microenvironment and endometrial vascularization in the peri-implantation endometrium of infertile women with CE.

METHODS

This retrospective study involved 15 fertile women and 77 infertile patients diagnosed with CE based on CD138+ ≥1/10 high-power fields (HPFs). The CE patients were divided into Group 1 (CD138+ 1-4/10 HPFs, 53 cases) and Group 2 (CD138+ ≥5/10 HPFs, 24 cases). The expression levels of hypoxia-inducible factor 1α (HIF1α), vascular endothelial growth factor A (VEGFA), and vascular endothelial growth factor receptor 2 (VEGFR2) in peri-implantation endometrium were assessed by qRT-PCR and western blot analyses. Spatial levels of HIF1α, VEGFA, and VEGFR2 in various endometrial compartments was determined using immunohistochemistry and H-score analysis. Microvascular density (MVD) was determined using CD34 staining and scored using Image J. Finally, we used qRT-PCR to assess changes in the expression of HIF1α, VEGFA, and VEGFR2 in CE patients after treatment with first-line antibiotics.

RESULTS

Relative to Group 1 and control group, during the implantation window, protein and mRNA levels of HIF1α, VEGFA, and VEGFR2 were markedly high in Group 2 (P<0.05). H-score analysis showed that HIF1α, VEGFA, and VEGFR2 in the luminal, glandular epithelium, and stromal compartments were markedly elevated in Group 2, comparing to control group and Group 1 (P<0.05). Moreover, markedly elevated MVD levels were observed in Group 2. Notably, the above indexes did not differ significantly in the control group versus Group 1. Treatment with antibiotics significantly suppressed the endometrial HIF1α and VEGFA levels in CE-cured patients.

CONCLUSIONS

Here, we for the first time report the upregulation of HIF1α, VEGFA, and VEGFR2, as well as excessive endometrial vascularization in the peri-implantation endometrium of CE patients. Our findings offer new insights into reduced endometrial receptivity in CE-associated infertility.