Chronic Endometritis: A Combined Histopathologic and Clinical Review of Cases From 2002 to 2007:

The correlation between chronic endometritis and Caesarean scar diverticulum

PURPOSE

To investigate the risk factors for Caesarean Scar Diverticulum (CSD) with Chronic Endometritis (CE) and the correlation between CE and clinical symptoms of CSD.

METHODS

The frequency of CE in 44 patients with CSD who underwent surgical treatment and 20 control women who underwent total hysterectomy was assessed and the clinical symptoms in the presence and absence of CE were compared. In accordance with the presence of one or more CD138-positive plasma cells per high-power field, CE was classified as mild or severe group.

RESULTS

According to multivariate analysis, the presence of mild CE (OR 8.963, 95 % CI 2.177-36.907, p = 0.002) or severe CE (OR 21.773, 95 % CI 2.285-207.419, p = 0.007) was significantly associated with CSD. Mild CE (OR 12.390, 95 % CI 1.158-132.511, p = 0.037) or severe CE (OR 22.463, 95 % CI 1.657-304.541, P = 0.019) or depth of diverticulum (OR 1.294, 95 % CI 1.003-1.668, p = 0.047) was associated with prolonged menstruation in patients with CSD. The degree of CE in patients with CSD was positively correlated with the days of prolonged menstruation (r = 0.552, p < 0.001) and negatively correlated with haemoglobin level (r = -0.408, p = 0.038).

CONCLUSIONS

CE was associated with CSD and its clinical symptoms, including prolonged menstruation and decreased haemoglobin. The severity of clinical symptoms of CSD is associated with endometrial inflammation.

Analysis of the Predictive Factors for Chronic Endometritis Recurrence in Infertile Women

PROBLEM

To identify the predictive factors for the recurrence of chronic endometritis (CE) in infertile women.

METHOD OF STUDY

In this case-control study, 1170 infertile women recovered from CE and underwent fertility treatment between December 2018 and August 2021. Among the 146 women (12.5%) who did not conceive or experienced pregnancy loss in 18 months after CE recovery, 105 consecutive women who underwent repeat endometrial biopsy for CD138 immunostaining and endometrial bacterial culturing were recruited. Thereafter, patients with and without CE recurrence were compared.

RESULTS

The total recurrence rate of CE was 29.5% (31 women). Multivariable logistic regression analysis to determine predictive factors for CE recurrence revealed that hysteroscopic surgery (odds ratio [OR], 0.10; 95% confidence interval [CI], 0.02-0.56; p = 0.0009) and pregnancy loss (OR, 4.13; 95% CI, 1.31-13.05; p = 0.016) were significantly associated with decreased and increased CE recurrence rates, respectively. Also, reexamination with CD138 immunostaining after 16-18 months (OR, 9.75; 95% CI, 1.47-64.64; p = 0.024) was significantly associated with increased CE recurrence rates. Among 49 patients without a history of pregnancy loss, the cumulative CE recurrence rates after 6, 12, and 18 months were 5.6%, 13.5%, and 20.4%, respectively.

CONCLUSIONS

We recommend reexamination with endometrial CD138 immunostaining in patients with pregnancy loss or long-term infertility during fertility treatment. Hysteroscopic surgery without antibiotic therapy for CE associated with intrauterine abnormalities is also recommended.

Endometrial congestion is the only hysteroscopic finding indicative of chronic endometritis

Chronic endometritis (CE), an inflammatory condition characterized by plasma cell infiltration within the endometrial stroma, is prevalent among women experiencing unexplained infertility or recurrent miscarriages. CE is traditionally diagnosed by endometrial biopsy using CD138 immunohistochemistry staining. Despite some studies suggesting hysteroscopy as an alternative diagnostic tool, its reliability compared with biopsy remains controversial. This study evaluated the diagnostic accuracy of hysteroscopy for CE by examining endometrial features, such as congestion, micropolyps, edema, and polyps, and comparing these with biopsy-confirmed cases of CE. This retrospective observational study was conducted at Toho University Omori Medical Center between June 2017 and November 2019 and included patients undergoing both hysteroscopy and histopathological examination. Endometrial congestion was identified as the only hysteroscopic finding significantly associated with CE, showing a moderate diagnostic agreement with biopsy results. These findings highlight the importance of further investigating hysteroscopic features of CE and their diagnostic implications and identify endometrial congestion as a potential predictive marker for 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.

Evaluation of Lipopolysaccharide and Interleukin-6 as Useful Screening Tool for Chronic Endometritis

Universal diagnostic criteria for chronic endometritis (CE) have not been established due to differences in study design among researchers and a lack of typical clinical cases. Lipopolysaccharides (LPSs) have been reported to cause inflammation in the reproductive systems of several animals. This study aimed to elucidate the influence of LPS in the pathogenesis of CE in humans. We investigated whether LPS affected cytokine production and cell proliferation in the endometrium using in vivo and in vitro experiments. LPS concentrations were analyzed between control and CE patients using endometrial tissues. LPS administration stimulated the proliferation of EM-E6/E7 cells derived from human endometrial cells. High LPS concentrations were detected in CE patients. LPS concentration was found to correlate with IL-6 gene expression in the endometrium. Inflammation signaling evoked by LPS led to the onset of CE, since LPS stimulates inflammatory responses and cell cycles in the endometrium. We identified LPS and IL-6 as suitable candidate markers for the diagnosis of CE.

Inflammatory responses in early pregnancy: Physiological and pathological perspectives

Background

Several conditions such as infertility, repeated implantation failure, and recurrent pregnancy loss can pose challenges in early pregnancy. These issues can be caused by the abnormal inflammatory response with various factors, including exogenous and endogenous agents, and pathogenic and nonpathogenic agents. In addition, they can be exacerbated by maternal immune response to the abovementioned factors.

Methods

This review aimed to assess the detrimental inflammatory effects of chronic endometritis, endometrial microbiota disturbance, and maternal immune system abnormalities on early pregnancy. Further, essential details such as ovulation, implantation, trophoblast invasion, and placental formation, were examined, thereby highlighting the beneficial roles of inflammation.

Main Findings

Excessive inflammation was associated with various early pregnancy disorders. Meanwhile, a lack of appropriate inflammation could also contribute to the development of different early pregnancy complications.

Conclusion

Excessive inflammation and insufficient inflammation can possibly lead to abnormal conditions in early pregnancy, and appropriate inflammation is required for a successful pregnancy.

Local immune recognition of trophoblast in early human pregnancy: controversies and questions

The role of the maternal immune system in reproductive success in humans remains controversial. Here we focus on the events that occur in the maternal decidua during the first few weeks of human pregnancy, because this is the site at which maternal leukocytes initially interact with and can recognize fetal trophoblast cells, potentially involving allorecognition by both T cells and natural killer (NK) cells. NK cells are the dominant leukocyte population in first-trimester decidua, and genetic studies point to a role of allorecognition by uterine NK cells in establishing a boundary between the mother and the fetus. By contrast, definitive evidence that allorecognition by decidual T cells occurs during the first trimester is lacking. Thus, our view is that during the crucial period when the placenta is established, damaging T cell-mediated adaptive immune responses towards placental trophoblast are minimized, whereas NK cell allorecognition contributes to successful implantation and healthy pregnancy.

Higher Prevalence of Chronic Endometritis in Women with Cesarean Scar Defect: A Retrospective Study Using Propensity Score Matching

(1) Background: A cesarean scar defect may cause localized inflammation of the endometrial tissue, and various researchers believe that the presence of a cesarean scar defect is associated with chronic endometritis. However, there is no report on the possible association between cesarean scar defects and chronic endometritis thus far. This study aimed to assess the role of having a cesarean scar defect in a person's susceptibility to chronic endometritis. (2) Methods: This retrospective propensity-score-matched study comprised 1411 patients with chronic endometritis that were admitted to Henan Provincial People's Hospital in China from 2020 to 2022. Based on whether a cesarean scar defect was present or not, all cases were assigned to the cesarean scar defect group or the control group. (3) Results: Of the 1411 patients, 331 patients with a cesarean scar defect were matched to 170 controls. All unbalanced covariates between groups were balanced after matching. Before matching, the prevalence of chronic endometritis in the cesarean scar defect group and in the control group was 28.8% and 19.6%, respectively. After correcting for all confounding factors, a logistic regression analysis showed that cesarean scar defect occurrence may increase the risk of chronic endometritis (odds ratio (OR), 1.766; 95% confidence interval (CI), 1.217-2.563; p = 0.003). After matching, the prevalence of chronic endometritis was 28.8% in the cesarean scar defect group and 20.5% in the control group. Thus, even after correcting for all confounding factors, the logistic regression analysis still showed that a cesarean scar defect remained an independent risk factor for chronic endometritis prevalence (OR, 1.571; 95% CI, 1.021-2.418; p = 0.040). The findings were consistent throughout the sensitivity analyses. (4) Conclusions: The present results suggest that the onset of a cesarean scar defect may increase the risk of chronic endometritis.

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.

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.

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.

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.

Fertility Awareness-Based Methods for Women's Health and Family Planning

Background

Fertility awareness-based methods (FABMs) educate about reproductive health and enable tracking and interpretation of physical signs, such as cervical fluid secretions and basal body temperature, which reflect the hormonal changes women experience on a cyclical basis during the years of ovarian activity. Some methods measure relevant hormone levels directly. Most FABMs allow women to identify ovulation and track this "vital sign" of the menstrual or female reproductive cycle, through daily observations recorded on cycle charts (paper or electronic).

Applications

Physicians can use the information from FABM charts to guide the diagnosis and management of medical conditions and to support or restore healthy function of the reproductive and endocrine systems, using a restorative reproductive medical (RRM) approach. FABMs can also be used by couples to achieve or avoid pregnancy and may be most effective when taught by a trained instructor.

Challenges

Information about individual FABMs is rarely provided in medical education. Outdated information is widespread both in training programs and in the public sphere. Obtaining accurate information about FABMs is further complicated by the numerous period tracking or fertility apps available, because very few of these apps have evidence to support their effectiveness for identifying the fertile window, for achieving or preventing pregnancy.

Conclusions

This article provides an overview of different types of FABMs with a published evidence base, apps and resources for learning and using FABMs, the role FABMs can play in medical evaluation and management, and the effectiveness of FABMs for family planning, both to achieve or to avoid pregnancy.

The Role of mTOR and eIF Signaling in Benign Endometrial Diseases

Adenomyosis, endometriosis, endometritis, and typical endometrial hyperplasia are common non-cancerous diseases of the endometrium that afflict many women with life-impacting consequences. The mammalian target of the rapamycin (mTOR) pathway interacts with estrogen signaling and is known to be dysregulated in endometrial cancer. Based on this knowledge, we attempt to investigate the role of mTOR signaling in benign endometrial diseases while focusing on how the interplay between mTOR and eukaryotic translation initiation factors (eIFs) affects their development. In fact, mTOR overactivity is apparent in adenomyosis, endometriosis, and typical endometrial hyperplasia, where it promotes endometrial cell proliferation and invasiveness. Recent data show aberrant expression of various components of the mTOR pathway in both eutopic and ectopic endometrium of patients with adenomyosis or endometriosis and in hyperplastic endometrium as well. Moreover, studies on endometritis show that derangement of mTOR signaling is linked to the establishment of endometrial dysfunction caused by chronic inflammation. This review shows that inhibition of the mTOR pathway has a promising therapeutic effect in benign endometrial conditions, concluding that mTOR signaling dysregulation plays a critical part in their pathogenesis.

The Diagnostic Criteria for Chronic Endometritis: A Survey of Pathologists

While acute endometritis is a reasonably well-defined entity of ascending infection and attendant active inflammation, chronic endometritis is less well defined. As part of a broad effort to define and refine the diagnostic criteria and management of the disease, we conducted a survey of pathologists to understand the variability in diagnostic criteria and implications of the diagnosis of nonspecific, nonobstetric chronic endometritis. Members of national and international professional pathology societies were surveyed utilizing anonymous electronic surveys designed to examine diagnostic criteria, etiological understanding and treatment implications of a pathologic diagnosis of nonspecific, nonobstetric chronic endometritis. There was substantial variability among pathologists in the diagnostic criteria used for making a diagnosis of nonspecific, nonobstetric chronic endometritis, with 28.5% of pathologists using the presence of a single plasma cell for making the diagnosis. There was additional variability in the use of special stains, reporting in the presence of coexisting lesions and the hormonal stage of the endometrium. There were no differences between generalists and specialists in the diagnostic criteria used, except the significantly greater likelihood of specialists making the diagnosis in gestational endometrium. The substantial variability in diagnostic criteria for nonspecific, nonobstetric chronic endometritis among pathologists, including among gynecologic pathologists, has the potential to confound the management of patients. Standardization of diagnostic criteria for chronic endometritis is essential to understand the implications of the diagnosis.

Redefining chronic endometritis: the importance of endometrial stromal changes

OBJECTIVE

To develop diagnostic criteria for chronic endometritis and compare the prevalence of chronic endometritis between women with recurrent pregnancy loss (RPL) and controls.

DESIGN

Cohort study.

SETTING

Single academic fertility center.

PATIENTS

Women with unexplained RPL (two or more pregnancy losses) and prospectively recruited controls without a history of RPL or infertility.

INTERVENTIONS

Endometrial samples were stained with hematoxylin and eosin and CD138. A pathologist blinded to patient history recorded the number of plasma cells per 10 high-power fields (HPFs). In addition, the presence or absence of endometrial stromal changes was documented.

MAIN OUTCOME MEASURE

Prevalence of chronic endometritis.

RESULTS

Endometrial samples from 50 women with unexplained RPL and 26 controls were evaluated. When chronic endometritis was defined as the presence of one or more plasma cells per 10 HPFs, 31% of controls and 56% of women with RPL met the criterion. When both endometrial stromal changes and plasma cells were required for a diagnosis of chronic endometritis, no controls and 30% of women with RPL met the criteria.

CONCLUSIONS

Although rare plasma cells were found in biopsy samples from controls, the presence of both plasma cells and endometrial stromal changes was limited to the RPL cohort. We propose that chronic endometritis be defined as the presence of one or more plasma cells per 10 HPFs in the setting of endometrial stromal changes. With the use of these strict diagnostic criteria, women with RPL have a significantly higher rate of chronic endometritis, supporting an association between chronic endometritis and RPL.

Histological diagnostic criterion for chronic endometritis based on the clinical outcome

BACKGROUND

The diagnostic criteria of chronic endometritis remain controversial in the treatment for infertile patients.

METHODS

A prospective observational study was conducted in a single university from June 2014 to September 2017. Patients who underwent single frozen-thawed blastocyst transfer with a hormone replacement cycle after histological examination for the presence of chronic endometritis were enrolled. Four criteria were used to define chronic endometritis according to the number of plasma cells in the same group of patients: 1 or more (≥ 1) plasma cells, 2 or more (≥ 2), 3 or more (≥ 3), or 5 or more (≥ 5) in 10 high-power fields. Pregnancy rates, live birth rates, and miscarriage rates of the non-chronic endometritis and the chronic endometritis groups defined with each criterion were calculated. A logistic regression analysis was performed for live births using eight explanatory variables (seven infertility factors and chronic endometritis). A receiver operating characteristic curve was drawn and the optimal cut-off value was calculated.

RESULTS

A total of 69 patients were registered and 53 patients were finally analyzed after exclusion. When the diagnostic criterion was designated as the presence of ≥ 1 plasma cell in the endometrial stroma per 10 high-power fields, the pregnancy rate, live birth rate, and miscarriage rate were 63.0% vs. 30.8%, 51.9% vs. 7.7%, and 17.7% vs. 75% in the non-chronic and chronic endometritis groups, respectively. This criterion resulted in the highest pregnancy and live birth rates among the non-chronic endometritis and the smallest P values for the pregnancy rates, live birth rates, and miscarriage rates between the non-chronic and chronic endometritis groups. In the logistic regression analysis, chronic endometritis was an explanatory variable negatively affecting the objective variable of live birth only when chronic endometritis was diagnosed with ≥ 1 or ≥ 2 plasma cells per 10 high-power fields. The optimal cut-off value was obtained when one or more plasma cells were found in 10 high-power fields (sensitivity 87.5%, specificity 64.9%).

CONCLUSIONS

Chronic endometritis should be diagnosed as the presence of ≥ 1 plasma cells in 10 high-power fields. According to this diagnostic criterion, chronic endometritis adversely affected the pregnancy rate and the live birth rate.

Impact of chronic endometritis in infertility: a SWOT analysis

Chronic endometritis is a pathology often associated with reproductive failure, but there are still no clear recommendations on whether its inclusion in the initial study of infertile couples is necessary. In this discussion paper, based on a SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis, the different aspects of the repercussions of chronic endometritis in fertility are evaluated. To avoid possible subjectivity in the analysis and results of this study, the researchers followed the Oxford criteria for the evaluation of evidence. The results from the evaluation of the reviewed literature seem to indicate that, pending new evidence, it would be advisable not to include chronic endometritis in the initial baseline study before assisted reproduction in order not to delay other assisted reproduction treatments. However, it would be advisable in cases of repetitive implantation failure and pregnancy loss after having undergone IVF with viable embryos and before continuing with costly reproductive processes, since results could be improved. The development of randomized studies assessing the impact of antibiotic treatment as a possible therapeutic option in infertile women with chronic endometritis, as well as the possible impact on endometrial microbiota and receptivity/implantation, would allow for the establishment of more precise clinical guidelines in this regard.

Endometrial causes of recurrent pregnancy losses: endometriosis, adenomyosis, and chronic endometritis

Chronic inflammatory processes affecting the endometrium, as encountered in endometriosis, adenomyosis, and chronic endometritis, alter endometrial receptivity. These disorders are associated with early pregnancy losses and possibly recurrent pregnancy losses (RPL). In the cases of endometriosis, other factors associated with the disease also are susceptible of causing miscarriages and possibly RPL, such as an impact of intrapelvic inflammatory processes affecting the oocyte and embryo in case of natural conception. Conversely these latter effects obviously are bypassed in case of assisted reproductive technology. Chronic inflammation of the endometrium in the condition known as chronic endometritis also causes early pregnancy losses and RPL with beneficial effects achieved when specific treatment is undertaken.

CHRONIC ENDOMETRITIS - MODERN CONCEPTS, PRINCIPLES OF MAINTENANCE. LITERATURE REVIEW

In our review article, we assessed the etiological factors of chronic endometritis, the most frequent manifestations of clinical and endoscopic data, the effectiveness of various diagnostic procedures and existing treatment methods. However, until now, many questions of the optimal algorithm for the diagnosis and treatment of this pathology remain open and require further study. In connection with the above, a certain practical and scientific interest may be of prospective studies assessing modern diagnostic and treatment methods for ChE, their impact on the number of unsuccessful reproductive outcomes of ART programs, taking into account the personal characteristics of the reproductive system of patients.

Harmful and beneficial effects of inflammatory response on reproduction: sterile and pathogen-associated inflammation

In reproduction, inflammatory processes play important roles in the development of many pregnancy complications such as preterm labor/birth, recurrent pregnancy loss, recurrent implantation failure, and preeclampsia. Inflammation can be initiated by both microbial and non-microbial causes. Bacterial infection in the feto-maternal interface and uterus can provoke preterm labor/birth, miscarriage, and chronic endometritis. By contrast, inflammation without infection, or 'sterile inflammation,' can also lead to many kinds of complications, such as preterm labor/birth, miscarriage, or preeclampsia. Aberrant inflammation is facilitated by immune cells such as macrophages, dendritic cells, natural killer cells, and invariant natural killer T cells. In addition, cytokines, chemokines, and several kinds of inflammatory mediators are involved. On the other hand, appropriate inflammation is required for a successful offspring during the progression of the entire pregnancy. Herein, we discuss the relation between pregnancy and inflammation with immunological alterations. Understanding the role of inflammation in complications during pregnancy may establish new perspectives of the progress of normal pregnancy as well as treatments during pregnancy complications.

Relationship of chronic endometritis with chronic deciduitis in cases of miscarriage

BACKGROUND

The presence of chronic deciduitis (CD) was determined in patients diagnosed with or without chronic endometritis (CE) before pregnancy.

OBJECTIVE

To study the effect of CE on decidua in cases of miscarriage.

METHODS

Decidual tissue was obtained from the patients who miscarried at the first pregnancy within a year after the diagnosis of the presence or absence of CE. The number and distribution pattern of plasma cells stained with CD138 in decidual tissue in 10 high-power fields (HPFs) was examined. The prevalence of CD diagnosed with four different grade; grade 0, no plasma cell in 10 HPFs, thus Non-CD;grade 1, rare single plasma cells; grade 2, rare clusters or more than 5 single cells total; and grade 3, many plasma cells with more than 5 clusters, were examined and compared between Non-CE and CE.

RESULTS

The incidence rate of CD of grade2 + 3 was significantly higher in CE than Non-CE (53.8%; 7/13 vs. 0%; 0/13, P < 0.01). Presence of clusters or a number of plasma cells in 10 HPFs of decidua showed a sensitivity of 53.8%, a specificity of 100%, a positive predictive value of 100%, and a negative predictive value of 68.4% for the diagnosis of CE.

CONCLUSION

Presence of clusters of plasma cells or five or more of plasma cells in decidua was found in more than half of CE, but not found in Non-CE. When CD with cluster or five or more of plasma cells is confirmed histologically in miscarriage decidual tissue, the presence of CE before the pregnancy should be suspected.

Therapeutic effects of resveratrol in Escherichia coli-induced rat endometritis model

Endometritis is an inflammatory disorder of the endometrial lining of the uterine tissue in postpartum stage. Endometritis mostly progresses subclinically and causes infertility through the disruption of the hormonal balance. It has been shown in many studies that resveratrol has anti-inflammatory and antioxidant properties. However, the possible beneficial effects of resveratrol in endometritis have not been determined yet. The aim of the present study is to evaluate the treatment potential of resveratrol in an experimentally induced endometritis model in rats. Endometritis was induced in 12-week-old female, nonpregnant, Sprague Dawley rats. The animals were divided into six groups: control (NaCl 0.9%) and endometritis (NaCl 0.9%), marbofloxacin + PGF_2α, marbofloxacin, marbofloxacin + resveratrol, and resveratrol groups. To induce endometritis, 5 mg/kg/s.c. progesterone was given for 5 days, and then Escherichia coli (50 μl, 1 × 10⁵ cfu/rat) was injected in the right cornu uteri following laparotomy. Sixteen hours after bacterial inoculation, the treatment protocol was applied for 14 days. At the end of the experiment, the total oxidant status (TOS) and total antioxidant status (TAS) were examined spectrophotometrically in uterus tissues. The severity of inflammation in uterus samples and follicular activity in ovarian tissues were histopathologically evaluated. In addition, serum cytokine levels were determined. While TAS in uterine tissue significantly increased in the resveratrol group when compared to that of the other groups (p < 0.05), there was no difference between the groups in TOS (p > 0.05). The inflammation of the endometrium and the numbers of corpus luteum in the endometritis group were highly significant when compared to those of the other groups (p < 0.05). The recovery of inflammation and follicular activity were similar to those of the other groups in resveratrol group. However, it was realized that resveratrol administration reduced serum cytokine levels. According to the results of the current study, resveratrol was found to be effective in the treatment of endometritis with its antioxidant and anti-inflammatory functions.

Review: Chronic endometritis and its effect on reproduction

AIM

Chronic endometritis (CE) is a disease of continuous and subtle inflammation characterized by the infiltration of plasma cells in the endometrial stromal area. Although the clinical significance of CE has been thought in clinical practice for a long time because it is either asymptomatic or presents with subtle symptoms, recent studies have shown the potential adverse effects of CE on fertility. In the present review, we focus on the concept, diagnosis, etiology, pathophysiology, diagnosis, impact on reproduction and treatment for it to understand CE.

METHODS

The published articles were reviewed.

RESULTS

The prevalence of CE has been found to be 2.8-56.8% in infertile women, 14-67.5% in women with recurrent implantation failure (RIF), and 9.3-67.6% in women with recurrent pregnancy loss. Microorganisms are thought to be a main cause of CE, since antibiotic treatment has been reported to be an effective therapy for CE. Common bacteria are frequently detected in the uterine cavity of CE patients by microbial culture. In CE endometrium, the prevalence of immune cells and decidualization has been reported to be modified, and these modifications are thought to adversely affect fertility. The gold standard for the diagnosis of CE is the histological detection of plasma cells in the stromal area of the endometrium in endometrial specimens, although universally accepted criteria for the diagnosis of CE have not been determined. The treatment currently thought to be most effective for the recovery of fertility in CE is administration of oral antibiotics. Patients whose CE has been cured have been reported to have a higher ongoing pregnancy rate, clinical pregnancy rate, and implantation rate compared with patients with persistent CE.

CONCLUSION

CE greatly affects implantation and impairs fertility. Antibiotic administration is an effective therapeutic option. Pregnancy rate in in vitro fertilization is improved when CE is cured by antibiotic.

Multiple Myeloma 1 Transcription Factor Is Superior to CD138 as a Marker of Plasma Cells in Endometrium

Chronic endometritis is characterized by plasma cell (PC) infiltration of endometrial stroma. Identification of PCs can be challenging by routine hematoxylin and eosin (H&E) stain due to the low numbers of PCs or to their being obscured by other cells in the stroma. CD138 is widely used as an ancillary immunohistochemistry stain to identify PCs; however, it has a high background reaction. In this study, multiple myeloma 1 (MUM1) transcription factor is introduced as an alternative PC marker in endometrial tissues. In this study, 311 endometrial biopsies, submitted to rule out chronic endometritis, were selected. They were divided into Group I (n = 87) and Group II (n = 224). Both had MUM1 and H&E while Group I also had accompanying CD138 stains. In both groups combined, MUM1 detected plasma cells in 48% of the cases, while CD138 and H&E identified the cells in 23% and 15% of the biopsies, respectively. In addition to having a clean background, MUM1 is a more sensitive stain than CD138 for detection of PCs in endometrium.

Endometritis: new time, new concepts

Endometritis is subdivided into two categories. Acute endometritis is symptomatic and characterized by microabscess formation and neutrophil invasion in the endometrial superficial epithelium, gland lumina, and uterine cavity. Chronic endometritis is rather silent and recognized as unusual plasmacyte infiltration in the endometrial stromal areas. Over the last decade, studies have disclosed the potential association between poor reproductive outcomes and endometritis, particularly chronic endometritis. The aim of this review is to address the current literature surrounding chronic endometritis and highlight recent advances in the research of this long-neglected gynecologic disease.

Evaluation of endometrium for chronic endometritis by using syndecan-1 in abnormal uterine bleeding

CONTEXT

Chronic endometritis is a condition observed in 3-10% of women with abnormal uterine bleeding (AUB). Diagnosis depends upon the histological detection of plasma cells within the inflammatory infiltrate in the endometrium. Plasma cells on H and E may be obscured by a mononuclear infiltrate, plasmacytoid stromal cells, abundant stromal mitosis, a pronounced predecidual reaction, menstrual features or secondary changes due to exogenous progesterone treatment prior to biopsy.

AIMS

The objective of this study was to determine utility of syndecan-1 in diagnosis of chronic endometritis in patients with AUB, and to see if any of the secondary histologic features in endometrial biopsy, correlated with the presence of plasma cells on immunohistochemistry (IHC).

MATERIALS AND METHODS

Fifty endometrial biopsies with a clinical diagnosis of AUB were taken. Endometrium in proliferative phase, secretory phase, endometrial polyps, and disordered proliferative endometrium were studied for the presence of plasma cells. IHC was done using syndecan-1. The secondary histologic features of chronic endometritis like gland architectural irregularity, spindled stroma, stromal edema and hemorrhage with the presence of plasma cells was statistically analysed. Values of P < 0.05 were considered as significant.

RESULTS

Plasma cells were seen in 11 (69%) of DPE, 8 (66%) of PEB, and 1 (7%) of normal proliferative endometrium and in 2 (40%) of secretory endometrium. Presence of stromal breakdown showed a significant association with plasma cells (P = 0.02) whereas gland architecture irregularity (P = 0.28), stromal edema (P = 0.71) and spindled stromal (P = 0.72) did not show a significant association.

CONCLUSIONS

Plasma cells were significantly present in AUB patients. Syndecan-1 maybe helpful in unusual cases, where chronic endometritis is suspected as the cause of clinically significant ongoing abnormal bleeding.

Limitations of the criteria used to diagnose histologic endometritis in epidemiologic pelvic inflammatory disease research

While endometrial neutrophils and plasma cells are criteria used to diagnose histologic endometritis in epidemiologic pelvic inflammatory disease (PID) research, plasma cell misidentification and nonspecificity may limit the accuracy of these criteria. Herein, we examined: (1) the identification of endometrial plasma cells with conventional methyl green pyronin-based methodology versus plasma cell-specific (CD138) immunostaining, (2) the prevalence of endometrial plasma cells among women at low risk for PID, and (3) endometrial leukocyte subpopulations among women diagnosed with acute or chronic histologic endometritis by conventional criteria. We observed an absence of CD138+ cells in 25% of endometrial biopsies in which plasma cells had been identified by conventional methodology, while additional immunohistochemical analyses revealed indistinguishable inflammatory infiltrates among women diagnosed with acute or chronic endometritis by conventional criteria. Among women considered at lower risk for PID development, flow cytometric analyses detected plasma cells in 30% of endometrial biopsy specimens, suggesting that these cells, even when accurately identified, only nonspecifically identify upper genital tract inflammatory processes. Combined, our findings underscore the limitations of the criteria used to diagnose histologic endometritis in PID-related research and suggest that satisfactory understanding of PID pathogenesis, treatment, and prevention is hindered by continued use of these criteria.

The value of hysteroscopy in diagnosis of chronic endometritis in patients with unexplained recurrent spontaneous abortion

OBJECTIVES

We performed this study in order to investigate the role of chronic endometritis (CE) in unexplained recurrent spontaneous abortion (RSA) and to determine the correlation between hysteroscopic and histologic findings of CE in patients with unexplained RSA. We also tried to find out the relation between CE and primary vs. secondary RSA.

STUDY DESIGN

One hundred and forty-two consecutive patients with unexplained RSA and 154 fertile women were enrolled in this study. All the patients and controls underwent hysteroscopy and, at the same time, endometrial biopsy. CE was suspected when hysteroscopy revealed signs of focal or diffuse endometrial hyperemia or endometrial endopolyps (less than 1mm in size). Histopathologic diagnosis of CE was based on superficial stromal edema, increased stromal density, and pleomorphic stromal inflammatory infiltrate dominated by lymphocytes and plasma cells. Results were compared between cases and controls as well as those with primary (n=61) and secondary (n=81) RSA.

RESULTS

Patients with RSA had a significantly higher incidence of CE both hysteroscopically (67.6% vs. 27.3%; p<0.0001) and pathologically (42.9% vs. 18.2%; p<0.0001). The sensitivity, specificity, positive predictive value and negative predictive value of hysteroscopy in the diagnosis of CE were found to be 98.4%, 56.23%, 63.5% and 97.82% respectively. Patients with secondary RSA had a higher prevalence of CE both pathologically (83.9% vs. 45.9%; p<0.0001) and hysteroscopically (58.1% vs. 24.6%; p<0.0001).

CONCLUSION

CE is associated with unexplained RSA. Hysteroscopy, with high sensitivity and acceptable specificity, is suitable for the diagnosis of CE in those with unexplained RSA. CE should be taken into consideration in those with secondary unexplained RSA.