Immunologic causes and thrombophilia in recurrent pregnancy loss

Advances in post-translational modifications and recurrent spontaneous abortion

Recurrent spontaneous abortion (RSA) is defined as two or more pregnancy loss, which affects approximately 1-2% of women's fertility. The etiology of RSA has not yet been fully revealed, which poses a great problem for clinical treatment. Post- translational modifications(PTMs) are chemical modifications that play a crucial role in the functional proteome. A considerable number of published studies have shown the relationship between post-translational modifications of various proteins and RSA. The study of PTMs contributes to elucidating the role of modified proteins in the pathogenesis of RSA, as well as the design of more effective diagnostic/prognostic tools and more targeted treatments. Most reviews in the field of RSA have only focused on RNA epigenomics research. The present review reports the latest research developments of PTMs related to RSA, such as glycosylation, phosphorylation, Methylation, Acetylation, Ubiquitination, etc.

Unraveling the H19/GAS1 axis in recurrent implantation failure: A potential biomarker for diagnosis and insight into immune microenvironment alteration

Recurrent implantation failure (RIF) presents a significant clinical challenge due to the lack of established diagnostic and therapeutic guidelines. Emerging evidence underscores the crucial role of competitive endogenous RNA (ceRNA) regulatory networks in non-cancerous female reproductive disorders, yet the intricacies and operational characteristics of these networks in RIF are not fully understood. This study aims to demystify the ceRNA regulatory network and identify potential biomarkers for its diagnosis. We analyzed expression profiles of three RNA types (long noncoding RNAs [lncRNAs], microRNAs [miRNAs], and mRNAs) sourced from the GEO database, leading to the identification of the H19-hsa-miR-301a-3p-GAS1 ceRNA network. This network demonstrates significant diagnostic relevance for RIF. Notably, the H19/GAS1 axis within this ceRNA network, identified through correlation analysis, emerged as a promising diagnostic marker, as evidenced by operating receiver operator characteristic (ROC) curve analysis. Further investigation into the binding potential of miR-301a-3p with H19 and GAS1 revealed a close association of these genes with endometrial disorders and embryo loss, as per the Comparative Toxicogenomics Database. Additionally, our immune infiltration analysis revealed a lower proportion of T cells gamma delta (γδ) in RIF, along with distinct differences in the expression of immune cell type-specific markers between fertile patients and those with RIF. We also observed a correlation between aberrant expression of H19/GAS1 and these immune markers, suggesting that the H19/GAS1 axis might play a role in modifying the immune microenvironment, contributing to the pathogenesis of RIF. In conclusion, the ceRNA-based H19/GAS1 axis holds promise as a novel diagnostic biomarker for RIF, potentially enhancing our understanding of its underlying mechanisms and improving the success rates of implantation.

Maternal-Fetal Compatibility in Recurrent Pregnancy Loss

Nowadays, recurrent pregnancy loss (RPL) is an undesirable condition suffered by many patients of reproductive age. In this scenario, certain immune cell populations and molecules, involved in maternal-fetal compatibility, have emerged as factors related with the pathogenesis of RPL. Among them, uterine Natural Killer cells (uNKs) appear to be of great relevance. These cells are involved in numerous processes during pregnancy, such as the remodeling of uterine spiral arteries or the control of trophoblast invasion. These functions are regulated by the interactions that these cells establish with the extravillous trophoblast, mainly through their Killer Immunoglobulin-like Receptors (KIRs) and the Human Leukocyte Antigen-C (HLA-C) molecules expressed by the embryo. A high level of polymorphism has been reported for both molecules involved in this interaction, with some of the possible KIR-HLA-C combinations being associated with an increased risk of RPL. However, the complexity of the maternal-fetal interface goes beyond this, as other HLA molecules also appear to be related to this reproductive pathology. In this review, we will discuss the role of uNKs in pregnancy, as well as the polymorphisms and clinical implications of KIR-HLA-C binding. We will also address the involvement of other, different HLA molecules in RPL, and the current advice on the appropriate management of patients with 'immunological mismatch', thus covering the main aspects regarding the involvement of maternal-fetal compatibility in RPL.

Endometrial protein expression and phosphorylation landscape decipher aberrant insulin and mTOR signalling in patients with recurrent pregnancy loss

RESEARCH QUESTION

What are the proteomic and phosphoproteomic differences between the endometrium of women with recurrent pregnancy loss (RPL) and the endometrium of healthy control women during the proliferative and secretory phases of the menstrual cycle?

DESIGN

In total, 54 endometrial samples were collected during the proliferative and secretory phases from women with RPL (n = 28) and healthy controls (n = 26). Comprehensive proteomic and phosphoproteomic analyses were conducted using label-free liquid chromatography-tandem mass spectrometry (n = 44), and verified through Western blotting (n = 10). Three comparison groups were established: total RPL endometrium versus total control endometrium; RPL proliferative endometrium versus control proliferative endometrium; and RPL secretory endometrium versus control secretory endometrium.

RESULTS

Differentially expressed proteins and differentially phosphorylated proteins were identified in the three comparison groups. Combining pathway enrichment, network analysis and soft clustering analysis, the insulin/cyclic nucleotide signalling pathway and AMPK/mTOR signalling pathway were identified as the major contributors to the aberration of RPL endometrium. Western blotting verified altered expression of four proteins: cAMP-dependent protein kinase type I-β regulatory subunit, adenylate cyclase type 3, 5'-AMP-activated protein kinase catalytic subunit α-2 and phosphatidate phosphatase LPIN2.

CONCLUSIONS

This exploratory study provides insights into the differentiated protein expression and phosphorylation profiles of the endometrium of women with RPL in both the proliferative and sectretory phases of the menstrual cycle. The results highlight potential proteins associated with the pathogenesis of RPL that may serve as potential indicators for RPL. The findings contribute to the identification of potential targets for RPL treatment as well as its pathogenesis.

Recognition of the Subtypes Classification and Diagnostic Signature Based on RNA N6-Methyladenosine Regulators in Recurrent Spontaneous Abortion

Recurrent spontaneous abortion (RSA) is a common reproductive disease in female patients that seriously affects the quality of life of patients. N6-methyladenosine (m6A), as the most common modification, plays an important role in various biological behaviors; however, the relationship between m6A and RSA is still unknown. In the present study, we utilized RNA sequencing data and clinical information of RSA patients and normal women in the GEO database to identify the expression profiles of m6A regulators in RSA. Based on the m6A regulators' expression profiles, we constructed a random forest model consisting of 4 genes to predict the prevalence of RSA patients, including FMR1, METTL14, LRPPRC, and RBMX. The predictive performance of the nomogram was constructed and validated. Not only that, consensus clustering was performed to divide RSA patients into 3 clusters based on the expression of m6A regulators and calculated the m6A scores and immune infiltration of patients in different clusters. It was found that the TH1-type immune response was dominant in the A cluster, the B-type immune activity was poor, and the C cluster was the strongest. In addition, on the basis of m6A typing, we further used the differentially expressed genes between clusters to perform consensus clustering verification, and the results were consistent with the previous findings. In conclusion, the m6A regulators played an indispensable role in the occurrence of RSA, and the m6A-based typing could effectively identify the immune characteristics of different RSA patients to a certain extent, providing a new direction and strategy for the diagnosis and treatment of RSA patients.

Thyroid autoimmunity and future pregnancy outcome in women of recurrent pregnancy loss: a meta-analysis

BACKGROUND

Thyroid autoimmunity (TAI) has been associated with the risk of recurrent pregnancy loss (RPL). This systematic review and meta-analysis was conducted to evaluate the influence of TAI on subsequent pregnancy outcome of women with RPL.

METHODS

A systematic search of Medline, Web of Science, and Embase was conducted to identify studies evaluating the influence of TAI on subsequent risk of pregnancy loss (PL) in women with RPL. Study quality was evaluated via the Newcastle-Ottawa Scale. A random-effects model was utilized to pool the results, accounting for heterogeneity.

RESULTS

Ten observational studies were included. Compared to women without thyroid autoantibodies, RPL women with TAI had a higher risk of PL in their subsequent pregnancy (risk ratio [RR]: 1.46. 95% confidence interval [CI]: 1.20 to 1.78, p < 0.001; I2 = 35%). Sensitivity analyses showed consistent results in studies with thyroid peroxidase antibody positivity (RR: 1.50, 95% CI: 1.23 to 1.82) and in studies with TAI assessed before pregnancy (RR: 1.28, 95% CI: 1.07 to 1.53). Subgroup analyses showed that the results were not significantly different in prospective and retrospective studies, in RPL defined as at least two or three PL, in euthyroid women and women with euthyroidism or subclinical hypothyroidism, in women with and without levothyroxine treatment, in studies reporting first-trimester or overall PL, and in studies with different quality scores (p for subgroup difference all > 0.05).

CONCLUSIONS

In women with RPL, positive for TAI may be related to a higher risk of PL in subsequent pregnancy.

Before Is Better: Innovative Multidisciplinary Preconception Care in Different Clinical Contexts

CONTEXT

Implementation of pre-conception care units is still very limited in Italy. Nowadays, the population's awareness of the reproductive risks that can be reduced or prevented is very low. Purpose and main findings: We presented a new personalized multidisciplinary model of preconception care aimed at identifying and possibly reducing adverse reproductive events. We analyzed three cohorts of population: couples from the general population, infertile or subfertile couples, and couples with a previous history of adverse reproductive events. The proposal involves a deep investigation regarding family history, the personal histories of both partners, and reproductive history.

PRINCIPAL CONCLUSIONS

Preconception care is still neglected in Italy and under-evaluated by clinicians involved in natural or in vitro reproduction. Adequate preconception counseling will improve maternal and fetal obstetrical outcomes.

Combined Parental Thrombophilia Gene Mutation Defects in Couples with Repeated Pregnancy Loss

Background

Several genetic mutations in female thrombotic defects have recently been shown to affect recurrent pregnancy loss (RPL); however, it is unclear which common parental mutations are involved in thrombosis-associated repeated pregnancy loss RPL.

Aims

In this study, the prevalence of some combined parental thrombophilia gene mutation defects was studied in couples with RPL.

Settings and Design

The observational study was done in babol infertility research center (Iran) in 2022.

Materials and Methods

Sixty-two infertile women with a history of RPL and their male partners (124 individuals) participated in this study. The frequencies of common defects associated with methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C, factor V Leiden, protein C, protein S and homocysteine were analysed in these couples.

Statistical analysis used

The data were statistically analysed using the Mann-Whitney test.

Results

Sixty-two couples (124 individuals) were analysed. 56.2% of couples with a history of RPL had MTHFR C677T and 23.1% had MTHFR A1298C. Forty percent of couples showed homocysteine deficiency and 12.5% protein C deficiency. Other genes tested were only observed in the mother or father but not both.

Conclusions

Results obtained with RPL couples demonstrate the importance of further investigating combined parental thrombophilia gene mutation defects (not only maternal).

A Successful Pregnancy Outcome After Continued Surveillance of Lupus Anticoagulant Antibodies in a Patient With Recurrent Pregnancy Loss: A Case Report and Literature Review

Recurrent pregnancy loss (RPL) can be a devastating experience for individuals trying to have children. Various potential causes contribute to the multifactorial pathogenesis of RPL, including chromosomal anomalies, endocrine conditions, autoimmunity, thrombophilias, and infectious agents. Antinuclear antibodies (ANAs) offer an unspecific clue to the underlying autoimmune pathogenic etiology of RPL. This case details a 40-year-old female with a history of RPL, fibromyalgia, and ANA positivity, who spontaneously developed lupus anticoagulant antibodies during her second trimester of pregnancy. Although the recommended American Society of Reproductive Medicine (ASRM) diagnostic criteria for initiating a thrombophilia evaluation was not formally met, the patient's maintenance of low-molecular-weight heparin (LMWH) throughout her pregnancy may have contributed to the success of the pregnancy. When treating a patient with RPL, consideration of the comprehensive clinical picture should precede the need to strictly adhere to published criteria for using non-proven clinical interventions. A risk-benefit analysis ought to be considered when offering patients additional medications that may come with some risks but could significantly improve the chances of a successful clinical outcome, such as live birth. We aim to provide evidence to promote greater flexibility in guidelines so that a patient's unique autoimmune etiologies of RPL are not overlooked.

Identification and verification of diagnostic biomarkers in recurrent pregnancy loss via machine learning algorithm and WGCNA

Background

Recurrent pregnancy loss defined as the occurrence of two or more pregnancy losses before 20-24 weeks of gestation, is a prevalent and significant pathological condition that impacts human reproductive health. However, the underlying mechanism of RPL remains unclear. This study aimed to investigate the biomarkers and molecular mechanisms associated with RPL and explore novel treatment strategies for clinical applications.

Methods

The GEO database was utilized to retrieve the RPL gene expression profile GSE165004. This profile underwent differential expression analysis, WGCNA, functional enrichment, and subsequent analysis of RPL gene expression using LASSO regression, SVM-RFE, and RandomForest algorithms for hub gene screening. ANN model were constructed to assess the performance of hub genes in the dataset. The expression of hub genes in both the RPL and control group samples was validated using RT-qPCR. The immune cell infiltration level of RPL was assessed using CIBERSORT. Additionally, pan-cancer analysis was conducted using Sangerbox, and small-molecule drug screening was performed using CMap.

Results

A total of 352 DEGs were identified, including 198 up-regulated genes and 154 down-regulated genes. Enrichment analysis indicated that the DEGs were primarily associated with Fc gamma R-mediated phagocytosis, the Fc epsilon RI signaling pathway, and various metabolism-related pathways. The turquoise module, which showed the highest relevance to clinical symptoms based on WGCNA results, contained 104 DEGs. Three hub genes, WBP11, ACTR2, and NCSTN, were identified using machine learning algorithms. ROC curves demonstrated a strong diagnostic value when the three hub genes were combined. RT-qPCR confirmed the low expression of WBP11 and ACTR2 in RPL, whereas NCSTN exhibited high expression. The immune cell infiltration analysis results indicated an imbalance of macrophages in RPL. Meanwhile, these three hub genes exhibited aberrant expression in multiple malignancies and were associated with a poor prognosis. Furthermore, we identified several small-molecule drugs.

Conclusion

This study identifies and validates hub genes in RPL, which may lead to significant advancements in understanding the molecular mechanisms and treatment strategies for this condition.

Downregulation of SEPTIN11 inhibits endometrial epithelial cell adhesive function in patients with elevated peripheral blood natural killer cell counts

RESEARCH QUESTION

What is the underlying mechanism of IVF and embryo transfer (IVF-ET) failure in patients with elevated peripheral blood natural killer cell (pNK) counts?

DESIGN

Patients undergoing IVF-ET cycles for tubal obstruction or pelvic adhesion (n = 486) were assigned to three groups: high (CD56+CD16+pNK >30% [n = 49]); medium (15< CD56+CD16+pNK ≤30% [n = 211]); and normal pNK groups (5≤ CD56+CD16+pNK ≤15% [n = 226]). Their general condition, previous pregnancy history and IVF outcomes were compared. Uterine fluid and endometrial tissue from patients in the high and normal pNK groups were collected during the mid-secretory phase and studied to elucidate the molecular mechanism underlying impaired endometrial receptivity.

RESULTS

The highest incidence of IVF-ET cycles (P < 0.0001) and biochemical pregnancy losses (P < 0.0001), and lowest implantation and clinical pregnancy rates (both P < 0.0001), were observed in patients with pNK over 30%. No significant difference was found in the number of previous miscarriages and rate of spontaneous miscarriage in IVF outcomes. Lower Septin11 (SEPT11) expression in the uterine fluid and endometrial epithelial cells (EEC), and higher endometrial IFN-γ, was observed in patients with high pNK. Ishikawa cell and human endometrial epithelial cell (HEEC) adhesion was inhibited after SEPT11 knock-down. Elevated IFN-γ decreased the SEPT11 protein levels in Ishikawa cells and HEECs.

CONCLUSIONS

CD56+CD16+pNK above 30% may be a threshold for adverse IVF-ET outcomes. Low SEPT11 expression in EEC inhibits cell adhesion, which may cause impaired endometrial receptivity in patients with elevated pNK. The level of SEPT11 in mid-secretory uterine fluid could serve as a non-invasive marker to assess endometrial receptivity in these patients.

Recurrent Pregnancy Loss Etiology, Risk Factors, Diagnosis, and Management. Fresh Look into a Full Box

Recurrent pregnancy loss is a complex health challenge with no universally accepted definition. Inconsistency in definitions involves not only the number of spontaneous abortions (two or three) that are accepted for recurrent pregnancy loss but the types of pregnancy and gestational age at miscarriage. Due to the heterogeneity of definitions and criteria applied by international guidelines for recurrent pregnancy loss, the true incidence of recurrent miscarriage, which is reported to range from 1% to 5%, is difficult to estimate. Moreover, the exact etiology of recurrent pregnancy loss remains questionable; thus, it is considered a polyetiological and multifactorial condition with many modifiable and non-modifiable factors involved. Even after thoroughly evaluating recurrent pregnancy loss etiology and risk factors, up to 75% of cases remain unexplained. This review aimed to summarize and critically analyze accumulated knowledge on the etiology, risk factors, relevant diagnostic options, and management approach to recurrent pregnancy loss. The relevance of various factors and their proposed roles in recurrent pregnancy loss pathogenesis remains a matter of discussion. The diagnostic approach and the management largely depend on the etiology and risk factors taken into consideration by a healthcare professional as a cause of recurrent miscarriage for a particular woman or couple. Underestimation of social and health consequences of recurrent pregnancy loss leads to compromised reproductive health and psychological well-being of women after miscarriage. Studies on etiology and risk factors for recurrent pregnancy loss, especially idiopathic, should be continued. The existing international guidelines require updates to assist clinical practice.

Pathophysiological, immunogenetic, anatomopathological profile of thrombophilia in pregnancy

Thrombophilic states have been associated with early and/or late pregnancy loss and possibly other severe obstetrical complications. Pregnancy-induced hypercoagulability, increased stasis, and the consequences of inherited and acquired thrombophilia are just a few of the factors that contribute to the development of thrombosis in pregnancy. In this review, we illustrate the impact that these factors have on the development of thrombophilia during pregnancy. We also explore how thrombophilia impact pregnancy outcomes. Next, we discuss how human leukocyte antigen G plays a part in thrombophilia during pregnancy by regulating cytokine release to prevent trophoblastic cell invasion and maintain local immunotolerance constant. Human leukocyte antigen class E is briefly explored with thrombophilia in pregnancy. Regarding the anatomopathologic aspect, we describe the different histopathological lesions of the placenta found in women with thrombophilia.

Dominant immune cells in pregnancy and pregnancy complications: T helper cells (TH1/TH2, TH17/Treg cells), NK cells, MDSCs, and the immune checkpoints

Pregnancy problems including recurrent pregnancy loss, repeated implantation failure and pre-eclampsia  are common problems in the reproductive ages. Different reasons such as genetic, immunological, and environmental agents and also infections could develop these complications. In those cases in which the cause of the abortion is diagnosed, the chance of a successful pregnancy is increased by eliminating defective factors. However, in patients with unknown causes, there may be an imbalance in immune cells pattern. As a matter of fact, an inappropriate immune response is often associated with a failed pregnancy. Hence, the focus of treatment is to increase tolerance, not to suppress maternal immune system. These findings are linked to an elevated number of Treg cells and immune checkpoints through normal pregnancy. The present review discusses the balance of myeloid-derived suppressor cells, natural killer cells, T cells, and immune checkpoints, and also targeting them to maintain pregnancy and prevent associated complications.

Prediction of risk factors for first trimester pregnancy loss in frozen-thawed good-quality embryo transfer cycles using machine learning algorithms

PURPOSE

Can the risk factors that cause first trimester pregnancy loss in good-quality frozen-thawed embryo transfer (FET) cycles be predicted using machine learning algorithms?

METHODS

This is a retrospective cohort study conducted at Sisli Memorial Hospital, ART and Reproductive Genetics Center, between January 2011 and May 2021. A total of 3805 good-quality FET cycles were included in the study. First trimester pregnancy loss rates were evaluated according to female age, paternal age, body mass index (BMI), diagnosis of infertility, endometrial preparation protocols (natural/artificial), embryo quality (top/good), presence of polycystic ovarian syndrome (PCOS), history of recurrent pregnancy loss (RPL), recurrent implantation failure (RIF), severe male infertility, adenomyosis and endometriosis.

RESULTS

The first trimester pregnancy loss rate was 18.2% (693/ 3805). The presence of RPL increased first trimester pregnancy loss (OR = 7.729, 95%CI = 5.908-10.142, P = 0.000). BMI, which is > 30, increased first trimester pregnancy loss compared to < 25 (OR = 1.418, 95%CI = 1.025-1.950, P = 0.033). Endometrial preparation with artificial cycle increased first trimester pregnancy loss compared to natural cycle (OR = 2.101, 95%CI = 1.630-2.723, P = 0.000). Female age, which is 35-37, increased first trimester pregnancy loss compared to < 30 (OR = 1.617, 95%CI = 1.120-2.316, P = 0.018), and female age, which is > 37, increased first trimester pregnancy loss compared to < 30 (OR = 2.286, 95%CI = 1.146-4,38, P = 0.016). The presence of PCOS increased first trimester pregnancy loss (OR = 1.693, 95%CI = 1.198-2.390, P = 0.002). The number of previous IVF cycles, which is > 3, increased first trimester pregnancy loss compared to < 3 (OR = 2.182, 95%CI = 1.708-2.790, P = 0.000).

CONCLUSIONS

History of RPL, RIF, advanced female age, presence of PCOS, and high BMI (> 30 kg/m2) were the factors that increased first trimester pregnancy loss.

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).

Identification of key genes and immune cell infiltration in recurrent implantation failure: A study based on integrated analysis of multiple microarray studies

PROBLEM

Recurrent implantation failure (RIF) refers to a challenging topic in assisted reproductive technology (ART), the etiology of which may be attributed to impaired endometrial receptivity; however, the precise pathogenesis of RIF has not been thoroughly elucidated.

METHOD OF STUDY

Four RIF microarray datasets were obtained from the Gene Expression Omnibus database and integrated by the "sva" R package. The differentially expressed genes (DEGs) were analyzed using the "limma" package and then GO, KEGG, GSEA, and GSVA were applied to perform functional and pathway enrichment analysis. The immune cell infiltration in the RIF process was evaluated by the CIBERSORT algorithm. Finally, the hub genes were identified through the CytoHubba and subsequently verified using two items of external endometrial data.

RESULTS

236 genes were differentially expressed in the endometrium of the RIF group. Functional enrichment analysis demonstrated that the biological functions of DEGs were mainly correlated to the immune-related pathways, including immune response, TNF signaling pathway, complement and coagulation cascades. Among the immune cells, γδ T cells decreased significantly in the endometrium of RIF patients. In addition, the key DEGs such as PTGS2, FGB, MUC1, SST, VCAM1, MMP7, ERBB4, FOLR1, and C3 were screened and identified as the hub genes involved in the pathogenesis of RIF.

CONCLUSIONS

Abnormal immune response regulation of endometrium contributes to the occurrence of RIF, and γδ T cells may be the pivotal immune cells causing RIF. At the same time, the novel hub genes identified will provide effective targets for the prediction and therapy of RIF.

The postpartum uterine ultrasonographic scale in assessment of uterine involution after cesarean section in treated thrombophilia pregnant patients at term

Background

Pregnancy is a prothrombotic condition which can be abnormally exaggerated in women with thrombophilia.

Methods

In a prospective study, patients who delivered at term, by cesarean section, between 1 October 2017 and 1 December 2021, who already had a diagnosis of thrombophilia before coming to our hospital, were included in the study group (n = 80). A similar number of nonthrombophilia patients (n = 80) without any history of thrombotic events, age‐ and para‐matched with the study group, were included in the control group. The postpartum uterine ultrasonographic scale (PUUS) values, in the first 24–48 h, were correlated with the patients' data.

Results

The P‐LCR (platelet large cell ratio), was significantly higher in the treated thrombophilia group (p = 0.042). There was no correlation between PUUS and complete blood count values, coagulation factors, maternal characteristics, or fetal outcomes, except for postpartum neutrophils (p = 0.047) and postpartum platelet count (p = 0.046).

Conclusions

Postpartum uterine involution was not significantly different, after cesarean section, between treated thrombophilia patients and nonthrombophilia patients. Involution correlated only with postpartum neutrophils and postpartum platelet count.

Research progress on ANXA5 in recurrent pregnancy loss

The incidence of recurrent pregnancy loss (RPL) in fertile women ranges from 1% to 5%, of which about 50% of them are due to unknown causes. The possible pathogenesis of RPL is an urgent problem to be solved in the clinical. Mutations or polymorphisms of certain genes in the coagulation mechanism are associated with susceptibility to thrombotic diseases and are one of the main reasons for the occurrence of RPL. Among them, the ANXA5 gene was newly studied and some single nucleotide polymorphisms (SNPs) in the promoter region of ANXA5 have been reported to be associated with RPL in multiple races. In this review, we summarized the research progress on the correlation between the SNPs in ANXA5 and RPL, hoping to provide some valuable guidance for the future studies.

Genetic markers for inherited thrombophilia related pregnancy loss and implantation failure in Indian population - implications for diagnosis and clinical management

AIM

The biology of recurrent pregnancy loss and recurrent implantation failure (RPL-RIF) is complex with multi-factorial etiology, with defective thrombosis being one of the most important and highly prevalent causes. The role of several thrombophilia related genes and variants associated with RPL-RIF is widely reported, and this study aimed to identify the risk associated with these genes in the Indian population.

METHODS

Next generation sequencing (NGS) was employed for the current study. NGS enables sequencing of multiple genes, identification of new variants, and establishment of genetic correlations with reproductive failure in diverse population groups. The present NGS based study evaluates association of twenty-nine genotypes of ten coagulation pathway genes (F2, F5, F13, MTR, MTRR, MTHFR, ANXA5, PROZ, SERPINE1 and VEGFA) with RPL-RIF in 540 female subjects - 474 patients with early recurrent pregnancy loss, late pregnancy loss, pregnancy complications in late gestation and recurrent implantation failure, with 66 controls.

RESULTS

The results emphasize inclusion of genotypes of seven thrombophilia genes (MTHFR, MTRR, MTR, ANXA5, PROZ, SERPINE1, VEGFA) for diagnosis of inherited thrombophilia risk for RPL-RIF in Indian population, as against the common practice of testing limited to F2, F5 and MTHFR genes.

CONCLUSION

Deriving risk magnitude from Combined Risk Analysis and interpretation of high-risk haplotypes are crucial components for evidence based personalized management such as selection of drugs and dosage, and prenatal or pre-implantation recommendations, for high-risk patients in fertility and obstetric clinics.

Uterine cytokine profiles after low-molecular-weight heparin administration are associated with pregnancy outcomes of patients with repeated implantation failure

INTRODUCTION

Low molecular-weight heparin (LMWH) plays a role in repeated implantation failure (RIF), but outcomes are controversial. LMWH can potentially modulate local immune responses associated with the establishment and maintenance of pregnancy. The study aimed to explore the effects of LWMH in uterine inflammatory cytokine profiles and pregnancy outcomes of patients with repeated implantation failure (RIF) but without thrombophilia.

METHODS

We compared clinical characteristics and reproductive outcomes among 326 patients with RIF, but not thrombophilia, undergoing frozen embryo transfer (FET) cycle with or without LMWH treatment. Endometrium secretions were aspirated from both groups after 3 days of progesterone administration before and after LMWH treatment. Cytokine mRNA expression was analyzed in primary endometrial cells in vitro.

RESULTS

The clinical and ongoing pregnancy rates did not significantly differ between the groups (31.5% vs. 24.4%, p = 0.15; 29.6% vs. 20.7%, p = 0.06). Concentrations of IL-6 and granulocyte-colony stimulating factor (G-CSF) in uterine secretions were significantly increased in the LWMH group, regardless of pregnancy outcomes (P < 0.05). And, in all patients treated with LWMH, those of secreted IL-6, IL-15 and G-CSF were significantly increased in pregnant group (P < 0.05). The expression of mRNA for G-CSF and IL-6 was significantly increased in human endometrial stromal cells in vitro (P < 0.05) after stimulation with LWMH (10 IU/mL).

CONCLUSIONS

Uterine cytokine profiles after LMWH administration are associated with pregnancy outcomes and LMWH may be beneficial for patients with three implantation failures who do not have coagulation disorders.

Pro-Inflammatory Signature in Decidua of Recurrent Pregnancy Loss Regardless of Embryonic Chromosomal Abnormalities

Recurrent pregnancy loss (RPL), especially the unexplained RPL, is associated with the disruption of maternal immune tolerance. However, little is known about the immune status at the decidua of RPL with embryonic chromosomal aberrations. Herein, mass cytometry (CyTOF) was used to interrogate the immune atlas at the decidua which was obtained from 15 RPL women-six with normal chromosome and nine with chromosomal aberrations-and five controls. The total frequency of CCR2^-CD11c^high macrophages increased, while CD39^high NK cells and CCR2^-CD11c^low macrophages decrease significantly in RPL when RPLs were stratified, compared with controls. Pro-inflammatory subsets of CD11c^high macrophages increased, while less pro-inflammatory or suppressive subsets decreased statistically in RPL decidua whenever RPLs were stratified or not. However, CD11c^high NK and CD161^highCD8⁺ T cells increased only in RPL with normal chromosome, while the inactivated and naive CD8⁺/CD4⁺ T cells were enriched only in RPL with chromosomal aberrations. A pro-inflammatory signature is observed in RPL decidua; however, differences exist between RPL with and without chromosomal abnormalities.

A review of the pathophysiology of recurrent implantation failure

Implantation is a critical step in human reproduction. The success of this step is dependent on a competent blastocyst, receptive endometrium, and successful cross talk between the embryonic and maternal interfaces. Recurrent implantation failure is the lack of implantation after the transfer of several embryo transfers. As the success of in vitro fertilization has increased and failures have become more unacceptable for patients and providers, the literature on recurrent implantation failure has increased. While this clinical phenomenon is often encountered, there is not a universally agreed-on definition-something addressed in an earlier portion of this Views and Reviews. Implantation failure can result from several different factors. In this review, we discuss factors including the maternal immune system, genetics of the embryo and parents, anatomic factors, hematologic factors, reproductive tract microbiome, and endocrine milieu, which factors into embryo and endometrial synchrony. These potential causes are at various stages of research and not all have clear implications or immediately apparent treatment.

DNA Methylation and Recurrent Pregnancy Loss: A Mysterious Compass?

Recurrent pregnancy loss (RPL) is a common and severe pathological pregnancy, whose pathogenesis is not fully understood. With the development of epigenetics, the study of DNA methylation, provides a new perspective on the pathogenesis and therapy of RPL. The abnormal DNA methylation of imprinted genes, placenta-specific genes, immune-related genes and sperm DNA may, directly or indirectly, affect embryo implantation, growth and development, leading to the occurrence of RPL. In addition, the unique immune tolerogenic microenvironment formed at the maternal-fetal interface has an irreplaceable effect on the maintenance of pregnancy. In view of these, changes in the cellular components of the maternal-fetal immune microenvironment and the regulation of DNA methylation have attracted a lot of research interest. This review summarizes the research progress of DNA methylation involved in the occurrence of RPL and the regulation of the maternal-fetal immune microenvironment. The review provides insights into the personalized diagnosis and treatment of RPL.

Decidual CXCR4+ CD56bright NK cells as a novel NK subset in maternal-foetal immune tolerance to alleviate early pregnancy failure

Natural killer (NK) cells preferentially accumulate at maternal-foetal interface and are believed to play vital immune-modulatory roles during early pregnancy and related immunological dysfunction may result in pregnant failure such as recurrent miscarriage (RM). However, the mechanisms underlying the establishment of maternal-foetal immunotolerance are complex but clarifying the roles of decidual NK (dNK) cells offers the potential to design immunotherapeutic strategies to assist RM patients. In this report, we analysed RNA sequencing on peripheral NK (pNK) and decidual NK cells during early pregnancy; we identified an immunomodulatory dNK subset CXCR4+ CD56bright dNK and investigated its origin and phenotypic and functional characteristics. CXCR4+ CD56bright dNK displayed a less activated and cytotoxic phenotype but an enhanced immunomodulatory potential relative to the CXCR4 negative subset. CXCR4+ CD56bright dNK promote Th2 shift in an IL-4-dependent manner and can be recruited from peripheral blood and reprogramed by trophoblasts, as an active participant in the establishment of immune-tolerance during early pregnancy. Diminished CXCR4+ dNK cells and their impaired ability to induce Th2 differentiation were found in RM patients and mouse models of spontaneous abortion. Moreover, adoptive transfer of CXCR4+ dNK cells to NK-deficient (Nfil3-/-) mice showed great therapeutic potential of CXCR4+ dNK via recovering the Th2/Th1 bias and reducing embryo resorption rates. The identification of this new dNK cell subset may lay the foundation for understanding NK cell mechanisms in early pregnancy and provide potential prognostic factors for the diagnosis and therapy of RM.

Recurrent pregnancy losses, a lasting cause of infertility

Recurrent pregnancy loss (RPL), defined as two to three spontaneous pregnancy terminations occurring before 12 weeks of gestation, affects approximately 1% of the general population. The causes may include congenital factors that originate with the quality of the gametes (sperm or oocyte) or the resulting embryo, or factors that originate within the uterus. Alterations of endometrial receptivity from endometriosis and/or endometritis, which are associated with impaired action of progesterone, have also been implicated in RPL. Finally, immunologic factors and thrombophilia, congenital and acquired, have also been suspected to cause RPL.