Application of chromosomal microarray analysis in products of miscarriage

Preimplantation genetic testing for aneuploidy in unexplained recurrent pregnancy loss: a systematic review and meta-analysis

IMPORTANCE

Preimplantation genetic testing for aneuploidy (PGT-A) to deselect aneuploid embryos in assisted reproductive technology (ART) treatment cycles may hold promise by augmenting pregnancy rates per transfer and reducing pregnancy loss rates for patients with unexplained recurrent pregnancy loss (RPL).

OBJECTIVE

To explore effectiveness of PGT-A in managing unexplained RPL by evaluating several key aspects: the likelihood of live birth in a subsequent spontaneous pregnancy, whether women with unexplained RPL have a higher rate of aneuploidy, whether euploid blastocysts offer comparable live birth rate (LBR) in patients with unexplained RPL, whether the endometrium is less selective in unexplained RPL loss, and whether PGT-A increases the LBR or reduces pregnancy losses until delivery.

DATA SOURCES

PubMed and Cochrane Library databases were searched from inception until June 2024.

STUDY SELECTION AND SYNTHESIS

Studies involving patients with ≥2 unexplained RPL who underwent ART with or without PGT-A or expectant management were included.

MAIN OUTCOME MEASURES

The primary outcome measure was the LBR. Secondary outcome measures were aneuploidy rate, clinical pregnancy rate, and clinical pregnancy loss rate.

RESULTS

Whether couples with unexplained RPL have higher embryo aneuploidy rates remains equivocal. Euploid blastocyst transfers yielded comparable clinical pregnancy loss rate (odds ratio [OR], 1.10; 95% confidence interval [CI], 0.57-2.13) and LBR (OR, 1.04; 95% CI, 0.74-1.44) in patients with and without unexplained RPL. Comprehensive chromosome analysis of products of conception shows similar aneuploidy rates between patients with and without RPL and does not support the less selective endometrium hypothesis. Preimplantation genetic testing for aneuploidy decreased clinical pregnancy loss rate (OR, 0.42; 95% CI, 0.27-0.67) and enhanced LBR per transfer (OR, 2.17; 95% CI, 1.77-2.65) and LBR per patient (OR, 1.85; 95% CI, 1.18-2.91) in patients with unexplained RPL.

CONCLUSION AND RELEVANCE

Current low-quality evidence suggests that PGT-A enhances LBR per transfer and per patient in unexplained RPL. Well-designed randomized controlled trials comparing ART with PGT-A vs. expectant management for unexplained RPL are warranted.

REGISTRATION NUMBER

CRD42021291546.

Role of genetic analysis of products of conception and PGT in managing early pregnancy loss

This article considers the addition of comprehensive 24-chromosomal microarray (CMA) analysis of products of conception (POC) to a standard evaluation for recurrent pregnancy loss (RPL) to help direct treatment towards expectant management versus IVF with preimplantation genetic testing for aneuploidies (PGT-A). The review included retrospective data from 65,333 miscarriages, a prospective evaluation of 378 couples with RPL who had CMA testing of POC and the standard workup, and data from an additional 1020 couples who were evaluated for RPL but did not undergo CMA testing of POC. Aneuploidy in POC explained the pregnancy loss in 57.7% (218/378) of cases. In contrast, the full RPL evaluation recommended by the American Society for Reproductive Medicine identified a potential cause in only 42.9% (600/1398). Combining the data from the RPL evaluation and the results of genetic testing of POC provides a probable explanation for the loss in over 90% (347/378) of women. Couples with an unexplained loss after the standard evaluation with POC aneuploidy accounted for 41% of cases; PGT-A may be considered after expectant management. Conversely, PGT-A would have a limited role in those with a euploid loss and a possible explanation after the standard workup. Categorizing a pregnancy loss as an explained versus unexplained loss after the standard evaluation combined with the results of CMA testing of POC may help identify patients who would benefit from expectant management versus PGT-A.

Experience of copy number variation sequencing applied in spontaneous abortion

PURPOSE

We evaluated the value of copy number variation sequencing (CNV-seq) and quantitative fluorescence (QF)-PCR for analyzing chromosomal abnormalities (CA) in spontaneous abortion specimens.

METHODS

A total of 650 products of conception (POCs) were collected from spontaneous abortion between April 2018 and May 2020. CNV-seq and QF-PCR were performed to determine the characteristics and frequencies of copy number variants (CNVs) with clinical significance. The clinical features of the patients were recorded.

RESULTS

Clinically significant chromosomal abnormalities were identified in 355 (54.6%) POCs, of which 217 (33.4%) were autosomal trisomies, 42(6.5%) were chromosomal monosomies and 40 (6.2%) were pathogenic CNVs (pCNVs). Chromosomal trisomy occurs mainly on chromosomes 15, 16, 18, 21and 22. Monosomy X was not associated with the maternal or gestational age. The frequency of chromosomal abnormalities in miscarriages from women with a normal live birth history was 55.3%; it was 54.4% from women without a normal live birth history (P > 0.05). There were no significant differences among women without, with 1, and with ≥ 2 previous miscarriages regarding the rate of chromosomal abnormalities (P > 0.05); CNVs were less frequently detected in women with advanced maternal age than in women aged ≤ 29 and 30-34 years (P < 0.05).

CONCLUSION

Chromosomal abnormalities are the most common cause of pregnancy loss, and maternal and gestational ages are strongly associated with fetal autosomal trisomy aberrations. Embryo chromosomal examination is recommended regardless of the gestational age, modes of conception or previous abortion status.

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.

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].

Fetal congenital gastrointestinal obstruction: prenatal diagnosis of chromosome microarray analysis and pregnancy outcomes

OBJECTIVE

The aim of this study was to investigate the incidence of chromosome anomalies in different types of congenital gastrointestinal obstruction and assess pregnancy outcomes of fetuses with congenital gastrointestinal obstruction.

METHODS

A total of 64 cases with gastrointestinal obstruction between January 2014 and December 2020 were enrolled in this study. They were divided into three groups according to sonographic images. Group A: isolated upper gastrointestinal obstruction; Group B: isolated lower gastrointestinal obstruction; Group C: non-isolated gastrointestinal obstruction. The rate of chromosome anomalies in different groups was calculated. Pregnant women with amniocentesis were followed up by medical records and telephone. The follow-up included pregnancy outcomes and development of the live born infants.

RESULT

From January 2014 to December 2020, there were 64 fetus with congenital gastrointestinal obstruction underwent chromosome microarray analysis(CMA), the overall detection rate of CMA testing was 14.1%(9/64). The detection rate of Group A, B and C were 16.2%, 0 and 25.0% respectively. 9 fetuses with abnormal CMA results were all terminated. Among 55 fetuses with normal chromosomes, 10(18.2%) fetuses were not found to have any gastrointestinal obstruction after birth. 17(30.9%) fetuses were diagnosed with gastrointestinal obstruction and underwent surgical treatment after birth, one of which had lower gastrointestinal obstruction combined with biliary obstruction and died due to liver cirrhosis. 11(20.0%) pregnancy were terminated due to multiple abnormalities. 5(9.1%) fetuses were intrauterine death. 3(5.5%) fetuses were neonatal deaths. 9(16.4%) fetuses were lost to follow-up.

CONCLUSION

It is crucial to understand whether the gastrointestinal tract abnormality is isolated or associated to other findings. The risk of chromosomal abnormalities in fetuses with isolated lower gastrointestinal obstruction is lower than upper gastrointestinal obstruction. While genetic abnormalities excluded, a promising prognosis is expected for fetuses with congenital gastrointestinal obstruction.

A chromosomal microarray analysis-based laboratory algorithm for the detection of genetic etiology of early pregnancy loss

Background: Chromosomal abnormalities are a major cause of early pregnancy loss. However, models synthesizing existing genetic technologies to improve pregnancy outcomes are lacking. We aim to provide an integrated laboratory algorithm for the genetic etiology of couples who experienced pregnancy loss. Methods: Over a 6-year period, 3,634 products of conception (POCs) following early pregnancy loss were collected. The clinical outcomes from a laboratory algorithm based on single nucleotide polymorphism (SNP) array, fluorescence in situ hybridization (FISH), and parental chromosomal karyotyping assays were comprehensively evaluated. Results: In total, 3,445 of 3,634 (94.8%) POCs had no maternal-cell contamination. Of those POCs, the detection rate of abnormal results was 65.2% (2,247/3,445), of which 91.2% (2,050/2,247) had numerical chromosomal abnormalities, 2.7% (60/2,247) had copy-number variations (CNVs) ≥10 Mb, 2.7% (61/2,247) had CNVs of terminal deletion and duplication, 2.8% (62/2,247) had CNVs <10 Mb, and 0.6% (14/2,247) had uniparental disomy. Furthermore, FISH confirmed 7 of the 60 POCs with mosaic aneuploids below 30% based on the SNP array results as tetraploid. Of the 52 POCs with CNVs of terminal deletion and duplication, 29 couples had balanced rearrangements based on chromosomal karyotyping. Conclusion: The integrated SNP array-based algorithm combined with optional FISH and parental chromosomal karyotyping is an effective laboratory testing strategy, providing a comprehensive and reliable genetic investigation for the etiology of miscarriage, regardless of the number of miscarriages and the method of conception.

Long-read sequencing: An effective method for genetic analysis of CYP21A2 variation in congenital adrenal hyperplasia

BACKGROUND

The sequence similarity between CYP21A2 gene and its inactive pseudogene CYP21A1P, and copy number variation (CNV) caused by unequal crossover, make it challenging to characterize the CYP21A2 gene through traditional methods. This study aimed to evaluate the clinical utility of the long-read sequencing (LRS) method in carrier screening and genetic diagnosis of congenital adrenal hyperplasia (CAH) by comparing the efficiency of the LRS method with the conventional multiplex ligation-dependent probe amplification (MLPA) plus Sanger sequencing approaches in CYP21A2 analysis.

METHODS

In a retrospective study, full sequence analysis of the CYP21A2 and CYP21A1P was performed for three pedigrees through long-range locus-specific PCR followed by LRS based on the Pacific Biosciences (PacBio, California, USA) single-molecule real-time (SMRT) platform, and the results were compared with those obtained from next-generation sequencing (NGS)-based whole exome sequencing (WES) and the traditional methods of MLPA plus Sanger sequencing.

RESULTS

The LRS method successfully identified seven CYP21A2 variants , including three single nucleotide variants (NM_000500.9:c.1451G>C p.(Arg484Pro), c.293-13A/C>G (IVS2-13A/C>G), c.518T>A p.(Ile173Asn)), one 111-bp polynucleotide insertion, one set of 3'URT variants (NM_000500.9:c.*368T>C, c.*390A>G, c.*440C>T, c.*443T>C) and two types of chimeric genes and straightforwardly depicted the inheritance patterns of these variants within families. Moreover, the LRS method enabled us to determine the cis-trans configuration of multiple variants in one assay, without the need to analyze additional family samples. Compared with traditional methods, this LRS method can achieve a precise, comprehensive and intuitive result in the genetic diagnosis of 21-hydroxylase deficiency (21-OHD).

CONCLUSION

The LRS method is comprehensive in CYP21A2 analysis and intuitive in result presentation, which holds substantial promise in clinical application as a crucial tool for carrier screening and genetic diagnosis of CAH.

Clinical Research into Treating Unexplained Recurrent Spontaneous Abortion during Early Pregnancy with the Qing Yi Tiao Mian Formula

OBJECTIVE

The present study aims to analyze the clinical effect of the Qing Yi Tiao Mian (QYTM) formula on unexplained recurrent spontaneous abortion (URSA) during early pregnancy and the immune balance of T lymphocytes.

METHODS

With their consent, 45 patients with URSA in weeks 4-9 of pregnancy were separated into three groups, i.e., the conventional fetal protection (n = 15), prednisone treatment (n = 10), and QYTM formula treatment (n = 20) groups. These patients received treatment once they had been diagnosed with an intrauterine pregnancy. The conventional fetal protection group was given progesterone (20 ∼ 40 mg daily injection) for four weeks. The prednisone treatment group was given progesterone (20 ∼ 40 mg daily injection) + prednisone (5 mg/d) for four weeks. The QYTM formula treatment group was given progesterone (20 ∼ 40 mg daily injection) + QYTM formula (one dose per day) for four weeks. In addition, women who had previously had a normal pregnancy were enrolled as a control group (n = 18). The success rate of the pregnancy in the first trimester was observed in each group, and the proportion of T lymphocytes in the peripheral blood before and after treatment was recorded.

RESULTS

Among the 20 patients with URSA in the QYTM formula treatment group, 19 remained pregnant. Thus, the success rate during early pregnancy was 95%, which was significantly higher than the conventional fetal protection (53.33%) and prednisone treatment (70%) groups. The CD8+ T and natural killer (NK) cells population in the URSA groups was higher compared with the control group (P < 0.01). The QYTM formula treatment significantly decreased the ratio of CD8+ T lymphocytes (P < 0.01) and NK cells (P < 0.01).

CONCLUSION

The QYTM formula significantly decreased the spontaneous abortion rate in patients with URSA during early pregnancy. The mechanism may be closely related to the inhibition of the killer lymphocytes' proliferation by CD8+ T lymphocytes and NK cells.

Optical Genome Mapping and Single Nucleotide Polymorphism Microarray: An Integrated Approach for Investigating Products of Conception

Conventional cytogenetic analysis of products of conception (POC) is of limited utility because of failed cultures, as well as microbial and maternal cell contamination (MCC). Optical genome mapping (OGM) is an emerging technology that has the potential to replace conventional cytogenetic methods. The use of OGM precludes the requirement for culturing (and related microbial contamination). However, a high percentage of MCC impedes a definitive diagnosis, which can be addressed by an additional pre-analytical quality control step that includes histological assessment of H&E stained slides from formalin-fixed paraffin embedded (FFPE) tissue with macro-dissection for chorionic villi to enrich fetal tissue component for single nucleotide polymorphism microarray (SNPM) analysis. To improve the diagnostic yield, an integrated workflow was devised that included MCC characterization of POC tissue, followed by OGM for MCC-negative cases or SNPM with histological assessment for MCC-positive cases. A result was obtained in 93% (29/31) of cases with a diagnostic yield of 45.1% (14/31) with the proposed workflow, compared to 9.6% (3/31) and 6.4% (2/31) with routine workflow, respectively. The integrated workflow with these technologies demonstrates the clinical utility and higher diagnostic yield in evaluating POC specimens.

Copy Number Variation Analysis of Euploid Pregnancy Loss

Objectives: Copy number variant (CNV) is believed to be the potential genetic cause of pregnancy loss. However, CNVs less than 3 Mb in euploid products of conceptions (POCs) remain largely unexplored. The aim of this study was to investigate the features of CNVs less than 3 Mb in POCs and their potential clinical significance in pregnancy loss/fetal death. Methods: CNV data were extracted from a cohort in our institution and 19 peer-reviewed publications, and only those CNVs less than 3 Mb detected in euploid pregnancy loss/fetal death were included. We conducted a CNV map to analyze the distribution of CNVs in chromosomes using R packages karyoploteR_1.10.5. Gene names and annotated gene types covered by those CNVs were mined from the human Release 19 reference genome file and GENECODE database. We assessed the expression patterns and the consequences of murine knock-out of those genes using TiGER and Mouse Genome Informatics (MGI) databases. Functional enrichment and pathway analysis for genes in CNVs were performed using clusterProfiler V3.12.0. Result: Breakpoints of 564 CNVs less than 3 Mb were obtained from 442 euploid POCs, with 349 gains and 185 losses. The CNV map showed that CNVs were distributed in all chromosomes, with the highest frequency detected in chromosome 22 and the lowest frequency in chromosome Y, and CNVs showed a higher density in the pericentromeric and sub-telomeric regions. A total of 5,414 genes mined from the CNV regions (CNVRs), Gene Ontology (GO), and pathway analysis showed that the genes were significantly enriched in multiple terms, especially in sensory perception, membrane region, and tight junction. A total of 995 protein-coding genes have been reported to present mammalian phenotypes in MGI, and 276 of them lead to embryonic lethality or abnormal embryo/placenta in knock-out mouse models. CNV located at 19p13.3 was the most common CNV of all POCs. Conclusion: CNVs less than 3 Mb in euploid POCs distribute unevenly in all chromosomes, and a higher density was seen in the pericentromeric and sub-telomeric regions. The genes in those CNVRs are significantly enriched in biological processes and pathways that are important to embryonic/fetal development. CNV in 19p13.3 and the variations of ARID3A and FSTL3 might contribute to pregnancy loss.

A new algorithm for the evaluation of recurrent pregnancy loss redefining unexplained miscarriage: review of current guidelines

PURPOSE OF REVIEW

Couples with recurrent pregnancy loss (RPL) are often referred to reproductive specialists to help determine the reason for their repeated losses. This review will help to develop a strategy that is effective in providing a diagnosis, efficient to administer, and cost-effective to the healthcare system.

RECENT FINDINGS

International societies have published different recommendations for the evaluation of RPL, they consider it appropriate to initiate an evaluation after two (or three) clinical miscarriages. On the contrary, the clinician who follows these guidelines will only be able to offer a possible explanation to fewer than half of the couples being evaluated. Recently, genetic testing of miscarriage tissue using 24-chromosome microarray (CMA) analysis at the time of the second pregnancy loss coupled with testing based on society guidelines has been shown provide an explanation in more than 90% of cases.

SUMMARY

New guidelines for the complete evaluation of RPL should consider adding 24-CMA testing on the miscarriage tissue. Providing couples with an explanation for recurrent loss assists them in dealing with the loss and discourages the clinician from instituting unproven therapies. Truly unexplained pregnancy loss can be reduced to less than 10% with this new algorithm. Incorporation of these strategies will result in significant cost savings to the healthcare system.

Genetic Testing for Aneuploidy in Patients Who Have Had Multiple Miscarriages: A Review of Current Literature

Recurrent pregnancy loss (RPL) is an obstetrical complication that affects about 3% of reproductive age couples. Genetic and non-genetic causes of RPL are multiple; however, aneuploidy is the most common obstetrical complication that can explain single and recurrent pregnancy loss (present in about 60% of recognized clinical pregnancies which result in a miscarriage). Parental karyotyping will only be of potential benefit for 2 to 5 percentage of RPL couples who are translocation carriers. Products of conception (POC) karyotype analysis has been used to direct management in RPL and has been shown to be cost-effective, but the technique has many limitations including high culture failure rate and maternal cell contamination. These limitations can be significantly reduced using POC chromosomal microarray (CMA) technology. We believe that POC genetic testing should be performed after the second and subsequent pregnancy loss using CMA. Although the results will not generally alter the course of treatment, the knowledge of the reason for the loss is of great emotional comfort to many patients. In addition, POC CMA performed in conjunction with a regular complete maternal RPL work-up will identify the group of truly unexplained RPL. Thus, only 10% of patients with RPL will complete an evaluation having a euploid loss and an otherwise normal work-up. This group of "truly unexplained RPL" would be ideal for new research trials and therapies. Pre-implantation genetic testing (PGT) technology has improved recently with day 5 trophectoderm biopsy as compared to biopsy on day 3 as well as with the addition of CMA and next-generation sequencing technologies. The most recent studies on PGT-SR (PGT-Structural rearrangement) show improved clinical and live birth rates per pregnancy, as well as decreased miscarriage rate for translocation carriers. PGT-A (PGT-aneuploidy) may have a limited role in RPL in cases with documented recurrent POC aneuploidy.

Copy number variation sequencing combined with quantitative fluorescence polymerase chain reaction in clinical application of pregnancy loss

PURPOSE

In this study, we evaluated the feasibility of the combining CNV-seq and quantitative fluorescence polymerase chain reaction (QF-PCR) for miscarriage analysis in clinical practice.

METHODS

Over a 35-month period, a total of 389 fetal specimens including 356 chorionic villi and 33 fetal muscle tissues were analyzed by CNV-seq and QF-PCR. Relationships between the risk factors (e.g., advanced maternal age, abnormal pregnancy history, and gestational age) and incidence of these chromosomal abnormalities were further analyzed by subgroup.

RESULTS

Clinically significant chromosomal abnormalities were identified in 58.95% cases. Aneuploidy was the most common abnormality (46.84%), followed by polyploidy (8.16%) and structural chromosome anomalies (3.95%). In sub-group analysis, significant differences were found in the total frequency of chromosomal abnormalities between the early abortion and the late abortion group, as well as in the distribution of chromosomal abnormalities between the advanced and the younger maternal age group. Meanwhile, the results of the logistic regression analysis identified a trend suggesting that the percentage of fetal chromosomal abnormalities is significantly higher in advanced maternal age, lesser gestational age, and lesser number of prior miscarriages.

CONCLUSION

Our study suggests that CNV-seq and QF-PCR are efficient and reliable technologies in the fetal chromosome analysis of miscarriages and could be used as a routine selection method for the genetic analysis of spontaneous abortion.

Genetic testing of products of conception in recurrent pregnancy loss evaluation

Genetic testing of products of conception (POC) has been proposed as a tool to be used in the evaluation of patients with recurrent pregnancy loss (RPL). Following a complete RPL evaluation, POC results may reveal an aneuploidy and provide an explanation for the miscarriage in more than 55% of cases. When the cytogenetic result of the pregnancy loss reveals a euploid pregnancy, management should be directed towards the identification of treatable abnormalities. Furthermore, the results of POC testing might better define a subgroup of patients with unexplained RPL who may benefit from expectant management versus preimplantation genetics (aneuploid unexplained RPL) or investigational therapy (euploid unexplained RPL).

Clinical utilization of chromosomal microarray analysis for the genetic analysis in subgroups of pregnancy loss

OBJECTIVE

The underlying etiologies of pregnancy loss are heterogeneous and in many cases unexplained. This study was to explore the genetic causes of early and late pregnancy loss using chromosomal microarray analysis (CMA).

METHODS

A cohort of 222 specimens of conceptions underwent genetic analysis using Affymetrix CytoScan 750 K arrays, which includes both SNP markers and copy number markers.

RESULTS

Of the 222-products of conception (POC), the overall detection rate for clinical significantly chromosomal anomalies was 40.54%, including 53 autosomal aneuploidy (23.87%), 16 sex chromosome aneuploidy (7.21%), 5 mutiple aneuploidy (2.25%), 4 triploidy (1.80%), and 12 pathogenic copy number variants (pCNVs) (5.41%). In addition, variants of uncertain significance and loss of heterozygosity were detected in 9 samples and 2 samples, respectively. The detection rates for total chromosomal abnormalities, autosomal aneuploidy, sex chromosome aneuploidy, multiple aneuploidy, and triploidy in specimens of early pregnancy loss was higher than that of late pregnancy loss, while had lower detection rate of pCNVs. Moreover, the detection rate in POC of mothers younger than 35 years was lower than that of advanced maternal age. The detection rate was 40.57% in POC of mothers with adverse pregnancy histories, in which was comparable with that of mothers without adverse pregnancy histories.

CONCLUSIONS

CMA yielded a superior detection rate in early pregnancy loss than that of late pregnancy loss. Moreover, the incidence of chromosome abnormality in cases with advanced maternal age was higher than that of cases with younger maternal age, while adverse pregnancy history seemed not to be the factors affecting the detection rate for chromosomal abnormality in pregnancy loss.