Traditional and molecular chromosomal abnormality analysis of products of conception in spontaneous and recurrent miscarriage

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

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

IGF2BP3 participates in the pathogenesis of recurrent spontaneous abortion by regulating ferroptosis

The aberrant invasive capability of trophoblast cells is widely acknowledged as a primary mechanism underlying RSA. Recently, IGF2BP3 has been implicated in various cancers due to its influence on cellular invasion and migration. However, whether IGF2BP3 involve in the occurrence of RSA and the specific functions it assumes in the development of RSA remain elusive. In our study, we firstly collected villous tissues from RSA and those with normal pregnancies individuals to performed Protein sequencing and then detected the expression of IGF2BP3 through Western blot, qRT-PCR and immunohistochemistry. Secondly, we analyzed the single-cell data (GSE214607) to assess the expression of IGF2BP3 in invasive EVT trophoblasts. Thirdly, we utilized lentivirus technology to establish HTR-8/SVneo cell lines with stable IGF2BP3 knockdown and RNA-seq analysis was employed to investigate the GO functional pathway enrichment of IGF2BP3. Meanwhile, the effect of IGF2BP3 knockdown on trophoblast cells apoptosis, migration, and ferroptosis was evaluated through functional experiments. Additionally, LPS-induced abortion animal model was constructed to evaluate IGF2BP3 expression in placental tissues. A significant downregulation of IGF2BP3 was observed in the villous tissues of RSA patient, a finding corroborated by subsequent single cell sequencing results. Furthermore, it suggested that IGF2BP3 may be involved in the migration and apoptotic processes of trophoblast cells. Mechanistic research indicated that IGF2BP3 knockdown could compromise GPX4 mRNA stability, leading to the promotion of ferroptosis. Finally, our investigation observed the down-regulation of IGF2BP3 expression in placental villous tissues of an LPS-induced abortion animal model. Our findings revealed that IGF2BP3 was downregulated in the villous tissues of RSA patients. Mechanically, down-regulation of IGF2BP3 may induce RSA by promoting GPX4-mediated ferroptosis and inhibiting trophoblast invasion and migration. Our study may provide new targets and research directions for the pathogenesis of RSA.

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.

Copy number variation sequencing for the products of conception: What is the optimal testing strategy

BACKGROUND

Copy number variation sequencing (CNV-seq) is crucial in prenatal diagnosis, but its limitations in detecting polyploidy, maternal cell contamination (MCC), and uniparental disomy (UPD) restrict its application in the analysis of products of conception (POCs). This study aimed to investigate an optimal genetic testing strategy for POCs in the era of CNV-seq.

METHODS

CNV-seq and quantitative fluorescent polymerase chain reaction (QF-PCR) were performed in all 4,211 spontaneous miscarriage cases. Different testing strategies were compared and the optimal testing strategies were proposed.

RESULTS

Of the 4,211 cases, 2561 (60.82%) exhibited clinically significant chromosomal abnormalities. CNV-seq alone, without QF-PCR, might misdiagnose 311 (7.39%) cases, including 278 polyploidy, 13 UPD, and 20 MCC. In 20 MCC cases identified by QF-PCR, CNV-seq successfully pinpointed the cause of miscarriage in 13 cases. Furthermore, in cases where QF-PCR suggested polyploidy, CNV-seq improved the diagnostic accuracy in 54 (1.28%) hypo/hypertriploidy cases. After comparing four different strategies, the sequential approach (initiating with CNV-seq followed by QF-PCR if necessary) emerged as advantageous, reducing approximately 70% of the cost associated with QF-PCR while maintaining result accuracy.

CONCLUSIONS

We propose an initial CNV-seq followed by QF-PCR if needed-an efficient and cost-effective strategy for the genetic analysis of POCs.

Clinical application of single nucleotide polymorphism microarray analysis in pregnancy loss in Northwest China

Background: Spontaneous abortion is the most common complication of early pregnancy. In this study, we aim to investigate the clinical application value of genetic diagnosis using single nucleotide polymorphism (SNP) microarray analysis on the products of conception and to characterize the types of genetic abnormalities and their prevalence in pregnancy loss in Northwest China. Methods: Over 48 months, we selected 652 products of conception, which included chorionic villi, fetal tissues, germ cell samples, amniotic fluid samples, cord blood samples, and a cardiac blood sample. We analyzed the distribution of chromosomal abnormalities leading to fetal arrest or abortion using SNP array. The patients were then categorized divided into groups based on maternal age, gestational age, number of miscarriages, and maternal ethnic background. The incidences of various chromosomal abnormalities in each group were compared. Results: Of the 652 cases, 314 (48.16%) exhibited chromosomal abnormalities. These included 286 cases with numerical chromosomal abnormalities, 24 cases with copy number variation, and four cases with loss of heterozygosity. Among them, there were 203 trisomy cases, 55 monosomy cases, and 28 polyploidy cases. In the subgroup analysis, significant differences were found in the frequency of numerical chromosomal abnormalities and copy number variation between the advanced and younger maternal age group as well as between the early and late abortion groups. Furthermore, we identified significant differences in the frequency of numerical chromosomal abnormalities between the first spontaneous abortion and recurrent miscarriage groups. However, there were no significant differences in the frequency of numerical chromosomal abnormalities between the Han and Uighur groups. Conclusion: Our research highlights chromosomal abnormalities as the primary cause of spontaneous abortion, with a higher incidence in early pregnancy and among women of advanced age. The use of SNP array analysis emerges as an effective and reliable technique for chromosome analysis in aborted fetuses. This method offers a comprehensive and dependable genetic investigation into the etiology of miscarriage, establishing itself as a valuable routine selection for genetic analysis in cases of natural abortions.

Genetic analysis of chorionic villus tissues in early missed abortions

Chromosomal abnormalities are the most common etiology of early spontaneous miscarriage. However, traditional karyotyping of chorionic villus samples (CVSs) is limited by cell culture and its low resolution. The objective of our study was to investigate the efficiency of molecular karyotyping technology for genetic diagnosis of early missed abortion tissues. Chromosome analysis of 1191 abortion CVSs in early pregnancy was conducted from August 2016 to June 2021; 463 cases were conducted via copy-number variations sequencing (CNV-seq)/quantitative fluorescent-polymerase chain reaction (QF-PCR) and 728 cases were conducted using SNP array. Clinically significant CNVs of CVSs were identified to clarify the cause of miscarriage and to guide the couples' subsequent pregnancies. Among these, 31 cases with significant maternal cell contamination were removed from the study. Among the remaining 1160 samples, 751 cases (64.7%) with genetic abnormalities were identified, of which, 531 (45.8%) were single aneuploidies, 31 (2.7%) were multiple aneuploidies, 50 (4.3%) were polyploidies, 54 (4.7%) were partial aneuploidies, 77 (6.6%) had submicroscopic CNVs (including 25 with clinically significant CNVs and 52 had variants of uncertain significance), and 8 cases (0.7%) were uniparental disomies. Our study suggests that both SNP array and CNV-seq/QF-PCR are reliable, robust, and high-resolution technologies for genetic diagnosis of miscarriage.

Reproductive outcomes in couples with sporadic miscarriage after embryonic chromosomal microarray analysis

OBJECTIVES

Chromosomal microarray analysis (CMA) has been widely applied to genetic diagnosis in miscarriages in clinical practice. However, the prognostic value of CMA testing of products of conception (POCs) after the first clinical miscarriage remains unknown. The aim of this study was to evaluate the reproductive outcomes after embryonic genetic testing by CMA in SM couples.

METHODS

In this retrospective study, a total of 1142 SM couples referred for embryonic genetic testing by CMA, and 1022 couples were successfully followed up after CMA.

RESULTS

Among 1130 cases without significant maternal cell contamination, pathogenic chromosomal abnormalities were detected in 680 cases (60.2%). The subsequent live birth rate did not differ significantly between couples with chromosomally abnormal and normal miscarriage (88.6% vs. 91.1%, p = .240), as well as the cumulative live birth rate (94.5% vs. 96.7%, p = .131). Couples with partial aneuploid miscarriage had a higher likelihood of spontaneous abortion both in the subsequent pregnancy (19.0% vs. 6.5%, p = .037) and cumulative pregnancies (19.0% vs. 6.8%, p = .044) when compared with couples with chromosomally normal miscarriage.

CONCLUSIONS

SM couples with chromosomally abnormal miscarriage manifested with a similar reproductive prognosis to couples with chromosomally normal miscarriage. Key messagesCMA testing of POCs could provide an accurate genetic diagnosis for couples with SM.The live birth rate of couples with partial aneuploid miscarriage was as high as couples with chromosomally normal miscarriage, despite a higher risk of adverse pregnancy event.Among couples with the most common single aneuploid miscarriage, the cumulative live birth rates of couples with trisomy 16, sex chromosomal abnormalities and trisomy 22 were 94.1%, 95.8% and 84.0%, respectively.

Recurrent MiscarriageGreen-top Guideline No. 17

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

Deletion of Insulin-like growth factor II mRNA-binding protein 3 participates in the pathogenesis of recurrent spontaneous abortion by inhibiting IL-10 secretion and inducing M1 polarization

Insulin-like growth factor II mRNA-binding protein 3 (IGF2BP3) has been proved to affect trophoblast function and embryonic development, but its role and potential mechanism in recurrent spontaneous abortion (RSA) are not clear. RSA is a complex reproductive disease, causing physical and mental damage to patients. In recent years, many studies have found that immune microenvironment is vital to maintain successful pregnancy in the maternal fetal interface. Therefore, this study aims to explore the role of IGF2BP3 in affecting macrophage polarization and its possible mechanism. In this article, we found that IGF2BP3 expression was decreased in placental villous samples of human and RSA mouse model, and knockdown of IGF2BP3 in HTR8/SVneo cells promotes M1 Mφ polarization. Combining with RNA sequencing analysis, we found that IGF2BP3 may regulate the Mφ polarization by affecting the expression of trophoblast cytokines, especially IL-10 secretion. Further mechanistic studies showed that knockdown of IGF2BP3 decreased expression of IL-10 by activating NF-κB pathway. Moreover, we found that M2 Mφ promote trophoblast invasion not IGF2BP3 dependent. Our study reveals the interaction between trophoblast cells and macrophages at the maternal-fetal interface of RSA patients, and will provide theoretical guidance for its diagnosis and treatment of RSA patients.

Cytogenetic Analysis of Sporadic First-Trimester Miscarriage Specimens Using Karyotyping and QF-PCR: A Retrospective Romanian Cohort Study

It is well known that first-trimester miscarriages are associated with chromosome abnormalities, with numerical chromosome abnormalities being the ones most commonly detected. Conventional karyotyping is still considered the gold standard in the analysis of products of conception, despite the extended use of molecular genetic techniques. However, conventional karyotyping is a laborious and time-consuming method, with a limited resolution of 5-10 Mb and hampered by maternal cell contamination and culture failure. The aim of our study was to assess the type and frequency of chromosomal abnormalities detected by conventional karyotyping in specimens of sporadic first-trimester miscarriages in a Romanian cohort, using QF-PCR to exclude maternal cell contamination. Long-term cultures were established and standard protocols were applied for cell harvesting, slide preparation, and GTG banding. All samples with 46,XX karyotype were tested for maternal cell contamination by QF-PCR, comparing multiple microsatellite markers in maternal blood with cell culture and tissue samples. Out of the initial 311 specimens collected from patients with sporadic first-trimester miscarriages, a total of 230 samples were successfully analyzed after the exclusion of 81 specimens based on unsuitable sampling, culture failure, or QF-PCR-proven maternal cell contamination. Chromosome abnormalities were detected in 135 cases (58.7%), with the most common type being single autosomal trisomy (71/135-52.6%), followed by monosomy (monosomy X being the only one detected, 24/135-17.8%), and polyploidy (23/135-17.0%). The subgroup analysis based on maternal age showed a statistically significant higher rate of single trisomy for women aged 35 years or older (40.3%) compared to the young maternal age group (26.1%) (p = 0.029). In conclusion, the combination of conventional karyotyping and QF-PCR can lead to an increased chromosome abnormality detection rate in first-trimester miscarriages. Our study provides reliable information for the genetic counseling of patients with first-trimester miscarriages, and further large-scale studies using different genetic techniques are required.

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).

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.

Ultrasound-guided Manual Vacuum Aspiration is an optimal method for obtaining products of conception from early pregnancy loss for cytogenetic testing

OBJECTIVE

The culture failure rate of conventional karyotyping in products of conception evacuated from early pregnancy loss by traditional electrical vacuum aspiration and/or dilation & curettage remains high. We aim to determine whether obtaining products of conception from early pregnancy loss via another evacuation approach, ultrasound-guided manual vacuum aspiration, could decrease the culture failure rate of karyotyping.

METHODS

For patients with early pregnancy loss, ultrasound-guided manual vacuum aspiration (Case group) and traditional electrical vacuum aspiration and/or dilation & curettage (Control group) were applied as surgical methods for pregnancy loss management respectively. The evacuated products of conception were subjected to cytogenetic karyotyping analysis. The primary outcome was the culture failure rate of karyotyping. Secondary outcomes included the chromosomal abnormality spectrum, maternal cell contamination, and complications from the manual vacuum aspiration procedure.

RESULTS

For the case group, 132 products of conception were genetically analyzed by conventional karyotyping. The culture failure rate was significantly lower than that of the control cohort (2.3% vs 7.4%, p = 0.027). 65.2% of cases were abnormal within the detection scope of karyotyping. The euploid female to male ratio was 0.82 (18:22), suggesting a lower likelihood of maternal cell contamination. The efficacy in achieving complete evacuation was 99.6%. There were no significant complications from the procedure.

CONCLUSION

Ultrasound-guided manual vacuum aspiration approach significantly decreased the culture failure rate of karyotyping and decreased maternal cell contamination tendency, enabling a high and accurate cytogenetic diagnosis. It is especially crucial when the cytogenetic analysis is required in the early pregnancy loss clinics.

Chromosomal Copy Number Variation Analysis in Pregnancy Products from Recurrent and Sporadic Miscarriage Using Next-Generation Sequencing

Chromosomal abnormality is one of the causes of fetal miscarriage. The potential differences of fetal chromosomal abnormalities in sporadic miscarriage (SM) and recurrent miscarriage (RM) remain unclear. The purpose of this study was to investigate copy number variations (CNVs) in SM and RM to provide useful genetic guidance for pregnancy and prenatal diagnosis. Four hundred eight samples of aborted fetuses were analyzed by CNV sequencing, and further functional enrichment analysis was performed. Chromosomal abnormalities were identified in 218 (53.4%) fetuses. There were 62 cases (15.2%) with structural chromosomal abnormalities, including 41 with VUS CNVs, 8 with pathogenic CNVs (pCNVs), and 5 with likely pCNVs. Duplications or deletions of 7p22, 8p22, 8p23, and Xp22.31 were significantly more common in RM cases and therefore believed to be related to RM. A total of 289 genes were identified, and 29 different functions were enriched as potential RM candidate genes and functions, which were mainly concentrated in 4 functional categories: chemokines and chemotaxis, protease activity and protein modification, defense response to bacterial and fungal infections, and immune response. The results of this study may improve our understanding of the etiology of RM and contribute to the establishment of a population-based genetic marker information for RM.

Vaginal Atopobium is Associated with Spontaneous Abortion in the First Trimester: a Prospective Cohort Study in China

Spontaneous abortion (SA) has received more and more attention in light of its increasing incidence. However, the causes and pathogenesis of SA remain largely unknown, especially for those without any pathological features. In this study, we characterized the vaginal microbiota diversity and composition of pregnant women in their first trimester and evaluated the association between the vaginal microbiota and SA before 12 weeks of gestation. Participants' bacterial profiles were analyzed by 16S rRNA gene sequencing in the V3-V4 regions at 5-8 weeks of gestation. A total of 48 patients with SA at 12 weeks of gestation were included as the study group, while 116 women with normal pregnancies (NPs) were included as a control group. The results indicated that the richness of the vaginal microbiome in SA patients was higher (Chao1, P < 0.05) and different in composition relative to that of women with NPs (unweighted UniFrac, R = 0.15, P < 0.01; binary Jaccard, R = 0.15, P < 0.01). Furthermore, the genus Apotobium was significantly enriched in SA patients. An extreme gradient-boosting (XGBoost) analysis was able to classify Atopobium-induced SA more reliably (area under the receiver operating characteristic curve, 0.69; threshold, 0.01%). Moreover, after adjusting for potential confounders, the results showed a robust association between Apotobium and SA (as a categorical variable [<0.01%]; adjusted odds ratio, 2.9; 95% confidence interval, 1.3 to 6.5; P = 0.01). In conclusion, higher vaginal Apotobium levels were associated with SA in the first trimester. IMPORTANCE Spontaneous abortion (SA) is the most common adverse pregnancy outcome in the first trimester. The causal drivers of SA have become a substantial challenge to reveal and overcome. We hypothesize that vaginal microbial dysbiosis is associated with SA, as it was related to several female reproductive disorders in previous studies. In our study, we characterized the vaginal microbiota of patients with SA at 12 weeks of gestation as the study group, and women with normal pregnancies were enrolled as a control group. Generally, significant differences were discovered in the vaginal microbiota between the two groups. Our study also revealed that Apotobium may play an important role in the pathogenesis of SA. To our knowledge, this study is the first detailed elaboration of the vaginal microbiota composition and vaginal Apotobium in association with SA. We believe that our findings will inspire more researchers to consider dynamic changes in the vaginal microbiota as critical features for further studies of nosogenesis not only for SA but also other reproductive diseases.

Recurrent pregnancy loss: fewer chromosomal abnormalities in products of conception? a meta-analysis

OBJECTIVE

To compare the prevalence of chromosomal abnormalities detected in products of conception (POCs) between recurrent pregnancy loss and sporadic pregnancy loss.

METHODS

A systematic search was performed in the PubMed and Embase databases from inception to December 31, 2020. Relevant studies analysing the association between the number of pregnancy losses and the incidence of chromosomal abnormalities were included. Independent data extraction was conducted and study quality was assessed. Meta-analyses were carried out to calculate odds ratios by using fixed- or random-effects models according to statistical homogeneity.

RESULTS

A total of 8320 POCs in 19 studies were identified for the meta-analyses. The incidence of chromosomal abnormalities in sporadic pregnancy loss was significantly higher than that in recurrent pregnancy loss. In subgroup analyses, the following studies reported a high incidence of abnormal outcomes of sporadic pregnancy loss: studies with ≥ 300 samples, studies published before 2014, studies conducted in European and American countries, and studies with analyses using conventional karyotype techniques. Moreover, the incidence of chromosomal abnormalities in women with two pregnancy losses was significantly higher than that in women with three or more pregnancy losses. However, there was no difference in the distribution of abnormal types between sporadic and recurrent pregnancy loss or between two and three or more pregnancy losses.

CONCLUSIONS

The prevalence of chromosomal abnormalities detected in POCs was lower in recurrent pregnancy loss than in sporadic pregnancy loss, and decreased with an increasing number of pregnancy losses.

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.

Analysis of Genomic Copy Number Variation in Miscarriages During Early and Middle Pregnancy

The purpose of this study was to explore the copy number variations (CNVs) associated with miscarriage during early and middle pregnancy and provide useful genetic guidance for pregnancy and prenatal diagnosis. A total of 505 fetal specimens were collected and CNV sequencing (CNV-seq) analysis was performed to determine the types and clinical significance of CNVs, and relevant medical records were collected. The chromosomal abnormality rate was 54.3% (274/505), among which the numerical chromosomal abnormality rate was 40.0% (202/505) and structural chromosomal abnormality rate was 14.3% (72/505). Chromosomal monosomy mainly occurred on sex chromosomes, and chromosomal trisomy mainly occurred on chromosomes 16, 22, 21, 15, 13, and 9. The incidence of numerical chromosomal abnormalities in ≥35 year-old age pregnant women was significantly higher than <35 year-old age group. The highest incidence of pathogenic CNV (pCNV) was found in fetuses at ≤6 weeks of pregnancy (5.26%), and the incidence of variants of unknown significance (VOUS) CNVs decreased gradually with the increase of gestational age. The rate of chromosomal abnormalities of fetuses in early pregnancy (59.5%) was higher than that of fetuses in middle pregnancy (27.2%) (p < 0.001). There were 168 genes in VOUS + pCNV regions. 41 functions and 12 pathways (p < 0.05) were enriched of these genes by Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis. Some meaningful genetic etiology information such as genes and pathways has been obtained, it may provide useful genetic guidance for pregnancy and prenatal diagnosis.

Proteomic and functional analysis of proteins related to embryonic development of decidua in patients with recurrent pregnancy loss

Recurrent pregnancy loss (RPL) is defined as the loss of two or more consecutive pregnancies before the 20 weeks of gestation. Recurrent pregnancy loss affects about 1-2% of couples trying to conceive; however, the mechanisms leading to this complication are largely unknown. Our previous studies using comparative proteomics identified 314 differentially expressed proteins (DEPs) in the placental villous. In this study, we identified 5479 proteins from a total of 34,157 peptides in decidua of patients with early recurrent pregnancy loss (Data are available via ProteomeXchange with identifier PXD023849). Further analysis identified 311 DEPs in the decidua tissue; and 159 proteins were highly expressed while 152 proteins were lowly expressed. These 311 proteins were further analyzed by using Ingenuity Pathway Analysis (IPA). The results suggested that 50 DEPs played important roles in the embryonic development. Upstream analysis of these DEPs revealed that AGT was the most important upstream regulator. Furthermore, protein - protein interaction (PPI) analysis of the embryonic development DEPs from the placental villous and decidua was performed in the STRING database. This study identified several proteins specifically associated with embryonic development in decidua of patients with early recurrent pregnancy loss. Therefore, these results provide new insights into potential biological mechanisms, that may ultimately inform recurrent pregnancy loss.

Lower chromosomal abnormality frequencies in miscarried conceptuses from frozen blastocyst transfers in ART

STUDY QUESTION

Are blastocyst culture and cryopreservation in ART associated with chromosomal abnormalities in miscarried products of conception (POC)?

SUMMARY ANSWER

Frozen blastocyst transfer in women aged 35 years or older and frozen embryo transfer (ET) (including both cleavage-stage embryo and blastocyst) in women aged <35 years are associated with decreased frequencies of embryonic chromosomal abnormalities in miscarried POC.

WHAT IS KNOWN ALREADY

Blastocyst culture and embryo cryopreservation have been previously associated with favorable ART treatment outcomes and widely applied in clinical practice. However, the association between these embryo manipulation procedures and embryonic chromosomal abnormalities has not been evaluated to the best of our knowledge.

STUDY DESIGN, SIZE, DURATION

This retrospective study included a total of 720 patients who underwent IVF/ICSI, and the retained POC were obtained. A single-nucleotide polymorphism (SNP)-based chromosomal microarray analysis (CMA) of all miscarried conceptuses was performed.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study was based on the Clinical Reproductive Medicine Management System/Electronic Medical Record Cohort Database (CCRM/EMRCD) at our center. In total, 720 miscarried POCs were collected from patients undergoing ART (including fresh cleavage-stage ET, fresh blastocyst transfer, frozen cleavage-stage ET and frozen blastocyst transfer), and the incidences and profiles of cytogenetic abnormalities in the miscarried conceptuses were measured via SNP-based CMA.

MAIN RESULTS AND THE ROLE OF CHANCE

The chromosomal abnormality rate in POC varied from 33.7% to 66.7% among the different ET strategies. In the patients aged ≥35 years, frozen blastocyst transfer was significantly associated with a lower incidence of chromosomal aberrations in the POCs (adjusted odds ratio (aOR): 0.171 (95% CI: 0.040-0.738); P = 0.018) than fresh blastocyst transfer. In the patients aged <35 years, frozen ET was significantly associated with a lower incidence of chromosomal aberrations than fresh ET in both cleavage-stage ET cycles and blastocyst transfers cycles (aOR: 0.545 (0.338-0.879), P = 0.013; and aOR: 0.357 (0.175-0.730), P = 0.005, respectively). Trisomy was the most frequent abnormal embryonic karyotype in the different ET strategies, and its frequency significantly differed among strategies (P < 0.05).

LIMITATIONS, REASONS FOR CAUTION

This study was retrospectively designed, and we cannot draw any definite conclusions from our results regarding the adequate safety of embryo cryopreservation in ongoing pregnancy.

WIDER IMPLICATIONS OF THE FINDINGS

To our knowledge, this is the first study assessing the associations of ET strategies with the probability of miscarriage associated with embryonic chromosomal abnormalities. However, the underlying mechanism of these associations is unknown; this study may promote research concerning ET strategies and promote comprehensive consultations and recommendations for patients.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Natural Science Foundation of China (Grant No.81571409), Science and Technology Research Project of Henan (Grant No. 172102310009) and Medical Science and Technology Research Project of Henan (Grant No. 201701005). The authors declare no competing interests.

TRIAL REGISTRATION NUMBER

N/A.

Recurrent spontaneous abortion related to balanced translocation of chromosomes: two case reports

Background

Recurrent spontaneous abortion (RSA) is often idiopathic, but structural chromosomal abnormality is an important nosogenesis. Balanced translocations or inversions can lead to unbalanced gametes depending on the specific recombination and segregation patterns during meiosis. An unbalanced karyotype in the conceptus of a couple when one partner has a structural chromosomal abnormality may result in failure to implant, miscarriage, or ongoing pregnancy of a fetus with an unbalanced karyotype.

Case presentation

We report two rare Han cases of RSA associated with balanced translocation of chromosomes. In case 1, a women who had had four spontaneous abortions, the karyotype was 46, XX, t (4;7) (q31;q22). In case 2, a women who had two spontaneous abortions and one stillborn fetus, the karyotype was 46, XX, t (3;15) (q12;p11.2), inv (5) (P13q13). The abnormal karyotype was not found in other chromosomes.

Conclusions

It is very important that couples with more than two miscarriages be provided with chromosomal analysis. Referring couples for karyotyping will rule out or confirm possible hereditary etiology and the source of chromosomal abnormalities in recurrent miscarriages.

Maternal germline factors associated with aneuploid pregnancy loss: a systematic review

BACKGROUND

Miscarriage describes the spontaneous loss of pregnancy before the threshold of viability; the vast majority occur before 12 weeks of gestation. Miscarriage affects one in four couples and is the most common complication of pregnancy. Chromosomal abnormalities of the embryo are identified in ∼50% of first trimester miscarriages; aneuploidy accounts for 86% of these cases. The majority of trisomic miscarriages are of maternal origin with errors occurring during meiotic division of the oocytes. Chromosome segregation errors in oocytes may be sporadic events secondary to advancing maternal age; however, there is increasing evidence to suggest possible maternal germline contributions to this.

OBJECTIVE AND RATIONALE

The objective of this review was to appraise critically the existing evidence relating to maternal germline factors associated with pregnancy loss secondary to embryo aneuploidy, identify limitations in the current evidence base and establish areas requiring further research.

SEARCH METHODS

The initial literature search was performed in September 2019 and updated in January 2021 using the electronic databases OVID MEDLINE, EMBASE and the Cochrane Library. No time or language restrictions were applied to the searches and only primary research was included. Participants were women who had suffered pregnancy loss secondary to numerical chromosomal abnormalities of the embryo. Study identification and subsequent data extraction were performed by two authors independently. The Newcastle-Ottawa Scale was used to judge the quality of the included studies. The results were synthesized narratively.

OUTCOMES

The literature search identified 2198 titles once duplicates were removed, of which 21 were eligible for inclusion in this systematic review. They reported on maternal germline factors having variable degrees of association with pregnancy loss of aneuploid origin. The Online Mendelian Inheritance in Man (OMIM) gene ontology database was used as a reference to establish the functional role currently attributed to the genes reported. The majority of the cases reported and included were secondary to the inheritance of maternal structural factors such as Robertsonian translocations, deletions and insertions. Germline factors with a plausible role in aneuploid pregnancy loss of maternal origin included skewed X-inactivation and CGG repeats in the fragile X mental retardation (FMR1) gene. Studies that reported the association of single gene mutations with aneuploid pregnancy loss were conflicting. Single gene mutations with an uncertain or no role in aneuploid pregnancy loss included mutations in synaptonemal complex protein 3 (SYCP3), mitotic polo-like kinase 4 (PLK4) and meiotic stromal antigen 3 (STAG3) spindle integrity variants and 5,10-methylenetetrahydrofolate reductase (MTHFR).

WIDER IMPLICATIONS

Identifying maternal genetic factors associated with an increased risk of aneuploidy will expand our understanding of cell division, non-disjunction and miscarriage secondary to embryo aneuploidy. The candidate germline factors identified may be incorporated in a screening panel for women suffering miscarriage of aneuploidy aetiology to facilitate counselling for subsequent pregnancies.

Effects of thrombophilia and antithrombotic therapy on embryonic chromosomal aberration rates in patients with recurrent pregnancy loss

BACKGROUND

Miscarriage occurs in 10-15% of pregnancies and recurrent pregnancy loss (RPL) occurs in 1% of couples hoping for a child. Various risk factors, such as thrombophilia, uterine malformation, and embryonic chromosomal aberration cause RPL. We hypothesized that antithrombotic therapy for RPL patients with thrombophilia would reduce miscarriage due to thrombophilia, which would reduce the total miscarriages and result in a relative increase in miscarriage due to embryonic chromosomal aberrations. In this study, we investigated the incidence of chromosomal aberrations in products of conception in RPL patients with and without antithrombotic therapy.

METHODS

We performed a single-center, retrospective review of cases diagnosed as miscarriage with embryo chromosome analysis between July 1, 2000, and May 31, 2019. Rates of chromosomal aberration were compared between RPL patients with and without thrombophilia or antithrombotic therapy.

RESULTS

One hundred and-ninety RPL cases were analyzed. The average age was 37.4 ± 4.3 years, and the average number of previous pregnancy losses was 2.2 ± 1.1. The overall chromosomal aberration rate was 67.4% (128/190). There was no difference in the chromosomal aberration rate between the factors for RPL, with or without thrombophilia, and antithrombotic therapy. Only advancing maternal age had significant correlation to increased embryo chromosomal aberration rates.

CONCLUSIONS

With or without antithrombotic therapy, miscarriage was caused by embryonic chromosome abnormalities at a certain rate. Antithrombotic therapy in RPL patients with thrombophilia may reduce abortions due to thrombophilia, which may also normalize the rate of embryonic chromosome aberrations in the subsequent miscarriages.

Detection of cytogenomic abnormalities by OncoScan microarray assay for products of conception from formalin-fixed paraffin-embedded and fresh fetal tissues

Background

The OncoScan microarray assay (OMA) using highly multiplexed molecular inversion probes for single nucleotide polymorphism (SNP) loci enabled the detection of cytogenomic abnormalities of chromosomal imbalances and pathogenic copy number variants (pCNV). The small size of molecular inversion probes is optimal for SNP genotyping of fragmented DNA from fixed tissues. This retrospective study evaluated the clinical utility of OMA as a uniform platform to detect cytogenomic abnormalities for pregnancy loss from fresh and fixed tissues of products of conception (POC).

Results

Fresh specimens of POC were routinely subjected to cell culture and then analyzed by karyotyping. POC specimens with a normal karyotype (NK) or culture failure (CF) and from formalin-fixed paraffin-embedded (FFPE) tissues were subjected to DNA extraction for OMA. The abnormality detection rate (ADR) by OMA on 94 cases of POC-NK, 38 cases of POC-CF, and 35 cases of POC-FFPE tissues were 2% (2/94), 26% (10/38), and 57% (20/35), respectively. The detected cytogenomic abnormalities of aneuploidies, triploidies and pCNV accounted for 50%, 40% and 10% in POC-CF and 85%, 10% and 5% in POC-FFPE, respectively. False negative result from cultured maternal cells and maternal cell contamination were each detected in one case. OMA on two cases with unbalanced structural chromosome abnormalities further defined genomic imbalances and breakpoints.

Conclusion

OMA on POC-CF and POC-FFPE showed a high diagnostic yield of cytogenomic abnormalities. This approach circumvented the obstacles of CF from fresh specimens and fragmented DNA from fixed tissues and provided a reliable and effective platform for detecting cytogenomic abnormalities and monitoring true fetal result from maternal cell contamination.

Current opportunities and new horizons into the genetic study of infertility

INTRODUCTION

An estimated 12.5% of couples experiencing fertility problems and almost 12% of reproductive age women have turned to health services at least once due to infertility. First trimester miscarriage is the most common clinical manifestation of infertility associated with a genetic cause.

PATIENTS, MATERIALS AND METHODS

The scientific research was conducted at A.S. Medical Center in Bucharest, Romania, between January 2016 and December 2018, on a representative group of 1264 Caucasian patients diagnosed with infertility, from which the study group was selected, consisting of 273 patients who were further genetically investigated.

RESULTS

Chromosomal instability, identified in 14% of patients, has been encountered most frequently in women (7%), and least often in fetuses (2%), unlike other chromosomal anomalies, identified in 55% of patients, which were more common in fetuses (27%) and least frequently in men (9%). Recurrent pregnancy loss due to genetic causes was identified in 53% of cases, being determined by chromosomal instability in 16% of cases and by other chromosomal anomalies in 37% of cases. Infertility due to a genetic cause was identified in 83% of cases, being determined by chromosomal instability in 17% of cases and by other chromosomal anomalies encountered in 66% of cases. In genetic risk pregnancies in evolution, fetal chromosomal anomalies were detected in 94% of cases, the most frequent being aneuploidy and polyploidy. Cytogenetic studies carried out on tissue fragments taken from aborted products of conception revealed the presence of a genetic cause in 57% of cases, an abnormal chromosome number being the most common (36%). The analysis of microdeletions of the long arm of the Y chromosome indicated that 5.5% of men with infertility are affected by this condition.

CONCLUSIONS

Although genetic tests are considered complex and expensive laboratory investigations, they are crucial in identifying the etiology of over 40% of infertility cases associated with genetic factors, as well as in the correct and effective management of infertility.

Recurrent pregnancy loss

Recurrent pregnancy loss is a distressing pregnancy disorder experienced by ~2.5% of women trying to conceive. Recurrent pregnancy loss is defined as the failure of two or more clinically recognized pregnancies before 20-24 weeks of gestation and includes embryonic and fetal losses. The diagnosis of an early pregnancy loss is relatively straightforward, although progress in predicting and preventing recurrent pregnancy loss has been hampered by a lack of standardized definitions, the uncertainties surrounding the pathogenesis and the highly variable clinical presentation. The prognosis for couples with recurrent pregnancy loss is generally good, although the likelihood of a successful pregnancy depends on maternal age and the number of previous losses. Recurrent pregnancy loss can be caused by chromosomal errors, anatomical uterine defects, autoimmune disorders and endometrial dysfunction. Available treatments target the putative risk factors of pregnancy loss, although the effectiveness of many medical interventions is controversial. Regardless of the underlying aetiology, couples require accurate information on their chances of having a baby and appropriate support should be offered to reduce the psychological burden associated with multiple miscarriages. Future research must investigate the pathogenesis of recurrent pregnancy loss and evaluate novel diagnostic tests and treatments in adequately powered clinical trials.

Detecting the Effects of Early-Life Exposures: Why Fecundity Matters

Prenatal exposures have meaningful effects on health across the lifecourse. Innovations in causal inference have shed new light on these effects. Here, we motivate the importance of innovation in the characterization of fecundity, and prenatal selection in particular. We argue that such innovation is crucial for expanding knowledge of the fetal origins of later life health. Pregnancy loss is common, responsive to environmental factors, and closely related to maternal and fetal health outcomes. As a result, selection into live birth is driven by many of the same exposures that shape the health trajectories of survivors. Lifecourse effects that are inferred without accounting for these dynamics may be significantly distorted by survival bias. We use a set of Monte Carlo simulations with realistic parameters to examine the implications of prenatal survival bias. We find that even in conservatively specified scenarios, true fetal origin effects can be underestimated by 50% or more. In contrast, effects of exposures that reduce the probability of prenatal survival but improve the health of survivors will be overestimated. The absolute magnitude of survival bias can even exceed small effect sizes, resulting in inferences that beneficial exposures are harmful or vice-versa. We also find reason for concern that moderately sized true effects, underestimated due to failure to account for selective survival, are missing from scientific knowledge because they do not clear statistical significance filters. This bias has potential real-world costs; policy decisions about interventions to improve maternal and infant health will be affected by underestimated program impact.

Evaluation of two aneuploidy screening tests for chorionic villus samples: Multiplex ligation-dependent probe amplification and fluorescence in situ hybridization

The vast majority of first-trimester pregnancy losses are the consequence of numerical aberrations in fetal chromosomes, which may involve nearly all chromosomes. Although commercial probes for all chromosomes are available for multiplex ligation-dependent probe amplification (MLPA) and fluorescence in situ hybridization (FISH) analyses, their use has rarely been reported for screening all 24 chromosomes for early fetal demise, especially by FISH. Here, we validated the ability of MLPA and FISH techniques as two low-cost aneuploidy screening methods for 24 chromosomes in 165 chorionic villus samples (CVSs). The results obtained by two methods were compared by the Chi-square test and the Kappa agreement test. Both methods gave conclusive results for all CVSs tested and showed highly consistent results (kappa = 0.890, p < 0.001). There was no statistically significant difference between the aneuploidy rate of the CVSs tested by the two methods (p = 0.180). Most of the samples showed fully concordant molecular karyotyping results (81.21%) between the two analytical methods, 10.91% had incompletely concordant results, and 7.88% had discordant results. The inconsistencies included segmental abnormalities, mosaicism, and polyploidy. Both assays used to screen 24 chromosomes were powerful techniques for detecting aneuploidy in CVSs. In terms of cost-effectiveness and diagnostic accuracy, the combination of subtelomeric (P036, P070) and centromeric (P181) MLPA assays is the better analytic strategy and follow-up analysis by FISH is recommended for MLPA-negative samples.

Risk factors for miscarriage among women attending an early pregnancy assessment unit (EPAU): a prospective cohort study

BACKGROUND

Miscarriage is the most common adverse outcome in early pregnancy; however, high proportion of miscarriages are classified as unexplained. In addition, pregnant women attending early pregnancy assessment units might be more vulnerable.

AIMS

The purpose of this study was to explore the risk factors that might be associated with miscarriage among women attending an early pregnancy assessment unit (EPAU).

METHODS

A prospective cohort study was undertaken. The study was conducted on women attending an EPAU at a large, tertiary hospital. A detailed lifestyle questionnaire was completed. In addition, data from validated psychometric scales were collected. Participants were followed up to determine pregnancy outcome. The relative risk was calculated to estimate the probability of having a miscarriage for all independent variables.

RESULTS

A total sample of 293 women were included in this study. Well-established risk factors for miscarriage were found in this group including advanced maternal age and high-risk pregnancy (i.e. threatened miscarriage and recurrent miscarriage). In addition, lack of emotional wellbeing did contribute to an increased risk of miscarriage. Conversely, presenting with nausea or low-medium energy levels early in pregnancy were associated with a decreased risk of miscarriage. Finally, our results did not find any association between stressful life events, general health and lifestyle factors in this group.

CONCLUSIONS

Our findings indicated that maternal, psychological and obstetric factors may have an influence on miscarriage among women attending an EPAU. The insight of a relationship between emotional wellbeing and miscarriage opens a window for prevention in this area.