Amniocentesis Sampling Research Articles

DNA concentrations in amniotic fluid according to gestational age and fetal sex: data from 2573 samples

PurposeIn some cases of prenatal genetic testing, an ample amount of fetal DNA is needed, to allow for parallel testing (conducting several genetic tests simultaneously). This study investigated the association between amniotic fluid DNA concentration and various factors. We aimed to define the required amount of amniotic fluid to be extracted in amniocentesis, to allow parallel testing throughout gestational weeks.MethodsDNA concentration was analyzed from amniocentesis samples taken during the years 2016–2022. Sex association was also analyzed in postnatal whole blood samples from a separate cohort. Theoretical minimum volume of amniotic fluid needed to ensure enough DNA for chromosomal microarray analysis and exome sequencing was calculated.ResultsWe focused our analysis on 2573 samples, which were taken during weeks 17–23 and 30–35. DNA concentrations increased from weeks 17 to 21, with relatively stable concentrations thereafter. Significantly higher DNA concentrations were seen in pregnancies of female fetuses. DNA concentrations in postnatal whole blood samples did not show this association. Across most weeks, the volume needed to extract 2 µg of DNA from 95% of the samples was about 34 ml.ConclusionDNA concentrations in amniotic fluid vary according to gestational age and are higher in pregnancies of female fetuses. This should be considered when determining the volume of fluid extracted and the timing of amniocentesis, with greater volumes needed in earlier stages of pregnancy.

Assessment of Combined Karyotype Analysis and Chromosome Microarray Analysis in Prenatal Diagnosis: A Cohort Study of 3710 Pregnancies.

The current study aimed to compare the characteristics of chromosome abnormalities detected by conventional G-banding karyotyping, chromosome microarray analysis (CMA), or fluorescence in situ hybridization (FISH)/CNVplex analysis and further explore the application value of combined karyotype analysis and CMA in prenatal diagnosis with a larger sample size. From March 2019 to March 2021, 3710 amniocentesis samples were retrospectively collected from women who accepted prenatal diagnosis at 16 to 22 + 6 weeks of pregnancy. The pregnant women underwent karyotype analysis and CMA. In the case of fetal chromosomal mosaicism, FISH or CNVplex analysis was utilized for validation. In total, 3710 G-banding karyotype results and CMA results from invasive prenatal diagnosis were collected. Of these, 201 (5.41%) fetuses with an abnormal karyotype were observed. The CMA analysis showed that the abnormality rate was 9.14% (340/3710). The detection rate of CMA combined with karyotype analysis was 0.35% higher than that of CMA alone and 4.08% higher than that of karyotyping alone. Additionally, 12 cases had abnormal karyotype analysis, despite normal CMA results. To further detect the chromosome mosaicism, we used FISH analysis to correct the karyotype results of case 1. Correspondingly, a total of 157 cases showed abnormal CMA results but normal karyotype analysis. We also found chromosomal mosaicism in 4 cases using CMA. Moreover, CNVplex and CMA demonstrated that representative case 15 was mosaicism for trisomy 2. Conventional G-banding karyotyping and CMA have their own advantages and limitations. A combination of karyotype analysis and CMA can increase the detection rate of chromosome abnormalities and make up for the limitation of signal detection.

Prenatal Diagnosis Using Chromosomal Microarray Analysis in High-Risk Pregnancies.

Background: To assess the value of chromosomal microarray analysis (CMA) during the prenatal diagnosis of high-risk pregnancies. Methods: Between January 2016 and November 2021, we included 178 chorionic villi and 859 amniocentesis samples from consecutive cases at a multiple tertiary hospital. Each of these high-risk singleton pregnancies had at least one of the following indications: (1) advanced maternal age (AMA; ≥35 years; 546, 52.7%); (2) fetal structural abnormality on ultrasound (197, 19.0%); (3) high-risk first- or second-trimester Down syndrome screen (189, 18.2%), including increased nuchal translucency (≥3.5 mm; 90, 8.7%); or (4) previous pregnancy, child, or family history (105, 10.1%) affected by chromosomal abnormality or genetic disorder. Both G-banding karyotype analysis and CMA were performed. DNA was extracted directly and examined with oligonucleotide array-based comparative genomic hybridization. Results: Aneuploidies were detected by both G-banding karyotyping and CMA in 42/1037 (4.05%) cases. Among the 979 cases with normal karyotypes, 110 (10.6%) cases had copy number variants (CNVs) in CMA, including 30 (2.9%) cases with reported pathogenic and likely pathogenic CNVs ≥ 400 kb, 37 (3.6%) with nonreported VOUS, benign, or likely benign CNVs ≥ 400 kb, and 43 (4.1%) with nonreported CNVs < 400 kb. Of the 58 (5.6%) cases with aneuploidy rearrangements, 42 (4.1%) were diagnosed by both G-banding karyotyping and CMA; four inversions, six balanced translocations, and six low mosaic rates were not detected with CMA. Conclusions: CMA is an effective first step for the prenatal diagnosis of high-risk pregnancies with fetal structural anomalies found in ultrasonography or upon positive findings.

Application of CNV-seq and chromosomal karyotyping in the prenatal diagnosis for carriers of balanced translocations

To assess the value of copy number variation sequencing (CNV-seq) and karyotyping in the prenatal diagnosis for carriers of balanced translocations. Clinical records of 135 amniocentesis samples of balanced translocation carriers undergoing simultaneous CNV-seq and karyotyping were analyzed. Chromosomal aberrations were defined as those can definitely lead to birth defects definitely, which included chromosomal numerical abnormality, large deletion/duplication and pathogenic copy number variations (pCNVs). The detection rates for karyotyping and CNV-seq were 4.44% (6/135) and 5.93% (8/135) respectively, and the latter had a detection rate of 1.48(2/135) higher than the former. A total of 68 fetal chromosomal translocations were detected by karyotying analysis. For couples carrying a balanced translocation, simultaneous CNV-seq and karyotyping is conducive to the detection of fetal chromosomal abnormalities and genetic counseling.

Noninvasive prenatal testing of hereditary colorectal cancer syndromes using cell-free DNA in maternal plasma.

This study aimed to establish a practical protocol for early noninvasive prenatal testing (NIPT) for fetuses at risk of Peutz-Jeghers syndrome or familial adenomatous polyposis, two classical types of hereditary colorectal cancer syndromes, for risk evaluation and whole-life monitoring. Target enrichment was performed using hybridization probes coordinating the serine-threonine kinase 11 gene region and APC gene region, with 1458 highly heterozygous Single Nucleotide Polymorphisms included. Semitarget amplification random sequencing was used for large fragment deletion detection. For relative haplotype dosage (RHDO) analysis, haplotype construction was performed by segmented haplotype estimation and imputation tool software, the circular binary segmentation algorithm was used for recombination event calculation, and Bayes factor was used for the determination of whether the fetus was affected. Haplotypes were successfully constructed in the nine recruited families with different pedigree characteristics, and the results for the RHDO analysis were consistent with the amniocentesis sampling detection results. The cell-free fetal DNA fraction can be detected as low as 2% in maternal plasma. This is the first NIPT assay on hereditary colorectal cancer syndromes based upon RHDO analysis.

Molecular studies on parental origin and cell stage of nondisjunction in sex chromosome aneuploidies

To study the parental origin and cell stage of nondisjunction in sex chromosome aneuploidies. Retrospectiving and analyzing the results of 385 cases of SCA confirmed by QF-PCR and karyotype analysis in the prenatal diagnosis center of Guangzhou Women and Children Medical Center from January 2015 to December 2020. The types of samples and prenatal diagnosis indications were analyzed. The parental origin and cell stage of nondisjunction in sex chromosome aneuploidies analyzed by comparing the short tandem repeat (STR) peak patterns of samples from fetuses and maternal peripheral blood. The results show that (1) There were 324 cases of nonmosaic SCA, 113 cases (113/324, 34.9%) were 45, XO, 118 cases (118/324, 36.4%) were 47, XXY, 48 cases (48/324, 14.8%) were 47, XXX and 45 cases (45/324, 13.9%) were 47, XYY. 68 (45/324, 60.2%) cases of 45, X were detected in villus samples. The other SCA cases were mainly detected in amniotic fluid samples. There were 61 mosaic SCA samples, 58(58/61, 95.1%) of mosaic SCA samples were mosaic 45, X. (2) The top two indications of 45, X cases are increased nuchal translucency(53/113, 46.9%) and fetal cystic hygroma (41/113, 36.3%), while the most common indication of other types of SCA was high risk of NIPT(170/272, 62.5%). (3) Among 45, X cases, there were 88 cases (88/113, 77.9%) inherit their single X chromosome from their mother and 25 cases (25/119, 22.1%) from their father. In 47, XXY samples, 47 cases (47/118, 39.8%) of chromosome nondisjunction occurred in meiosis stage Ⅰ of oocytes, 51 cases (51/118, 43.2%) occurred in meiosis stage Ⅰ of spermatocytes, and 20 cases (20/118, 16.9%) occurred in meiosis stage Ⅱ of oocytes. Among 47, XXX samples, 29 cases (29/48, 60.4%) of X chromosome nondisjunction occurred in meiosis stage Ⅰof oocytes, 15 cases (15/48, 31.3%) occurred in meiosis stage Ⅱ of oocytes, and 4 cases (4/48, 8.3%) occurred in meiosis stage Ⅱ of spermatocytes. In summary, the cases of 45, X were mainly diagnosed by villous samples for abnormal ultrasound findings. The other cases of SCA were mainly diagnosed by amniocentesis samples for abnormal NIPT results. Different types of SCA, the origin and occurrence period of sex chromosome nondisjunction were different.

Evidence for differential care in Down syndrome screening based on maternal origin: a population based survey in France

Abstract Background Previous studies showed disparities in prenatal screening for Down syndrome according to socio-economic status and maternal place of birth. Thus, it remains uncertain that those disparities are related to access difficulties or lack of information offered to women. Our objective was to assess the opportunity for informed choice regarding Down syndrome screening according to maternal place of birth. Methods Data were based on French national perinatal surveys of 2010 and 2016. These surveys include several questions relative to Down syndrome screening, such as measurement of nuchal translucency and realization of maternal serum screening. We considered that women had the opportunity for choice in case of realization or refusal of prenatal screening, or realization of amniocentesis or chorionic villous sampling. We considered that women had no opportunity for choice in case of ignorance of the realization of the tests, or if the screening has not been performed because not proposed, late prenatal follow-up, or another reason or unknown reason. We used multinomial logistic regression models to assess the association between the use of the tests and women country of birth. Results The proportion of women undergoing measurement of nuchal translucency or maternal serum screening was higher in women born in France than women born in another country. After adjustment on the year of the survey, maternal age, parity, education level and type of maternity, and after exclusion of women without adequate prenatal follow-up, the opportunity for making an informed choice for Down syndrome screening was higher for women born in France than women born in another European country (ORa 2.36; 95%CI,1.8-3.0), in Maghreb (ORa 4.01; 95%CI,3.4-4.8) or in another African country (ORa 3.52(2.8-4.3). Conclusions Disparities in the use of Down syndrome screening according to women place of birth are almost partly related to differences in the opportunity of an informed choice.

The Influence of Maternal Cell Contamination on Fetal Aneuploidy Detection Using Chip-Based Digital PCR Testing.

Prenatal samples obtained by amniocentesis or chorionic villus sampling are at risk of maternal cell contamination (MCC). In traditional prenatal analysis, MCC is recommended to be assayed by special tests, such as the short tandem repeat analysis and, if detected at a high level, may result in failed analysis report. The objective of this study was to test the ability of chip-based digital PCR to detect fetal aneuploidies in the presence of MCC. To determine the level of accuracy of MCC detection, an aneuploid male sample was subjected to serial dilution with an euploid female sample. DNA was extracted from prenatal samples and analyzed with QuantStudio 3D Digital PCR. Digital PCR analysis allowed the detection of trisomy 21, trisomy 18, and X monosomy accurately in samples with 90%, 85%, and 92% of MCC, respectively. Moreover, our results indicated that digital PCR was able to accurately confirm the presence of Y chromosome at up to 95% contamination. The amniotic fluid and chorionic villus sampling (CVS) received in our clinical laboratory was subjected to further analysis of MCC based on the aneuploidy assessment algorithm, resulting in the identification of 10 contaminated samples and four cases of true fetal mosaicism. We conclude that chip-based digital PCR analysis enables the detection of fetal aneuploidy with high levels of accuracy, even in cases of significant MCC. Importantly, the algorithm eliminates the need for maternal DNA and additional MCC tests, which reduces costs and simplifies the diagnostic procedure. The method is easy to set up and suitable for routine clinical practice.

Evidence of bacterial DNA presence in chorionic villi and amniotic fluid in the first and second trimester of pregnancy.

The sterile-womb dogma in uncomplicated pregnancy has been lively debated. Data regarding the in utero microbiome environment are based mainly on studies performed at the time of delivery. Aim: To determine whether human placenta and amniotic fluid are populated by a bacterial microbiota in the first and second trimesters of pregnancy. Materials & methods: We analyzed by next-generation sequencing method 24 and 29 samples from chorionic villus sampling (CVS) and amniocentesis (AC), respectively. The V3 region of the 16S rRNA gene was sequenced. Results: 37.5% of CVS and 14% of AC samples showed the presence of bacterial DNA. Conclusion: Our study suggests that bacterial DNA can be identified in the placenta and amniotic fluid during early prenatal life.

Potential Use of Cell Free Fetal DNA at 13 Short Tandem Repeats Loci for Noninvasive Prenatal Paternity Test

Background : Prenatal paternity test is mostly performed by using Amniocentesis or Chorionic Villus Sampling (CVS) methods. However, these methods require invasive procedures, which are potentially harmful for both the mother and the fetus. Currently, the invention of of Cell-Free Fetal DNA (cffDNA) has offered the opportunity of performing prenatal paternity test non-invasively. Materials and Methods : This study is a cross sectional descriptive study to detect cell free fetal DNA at 13 STR loci and at amelogenin gene to evaluate fetus gender, which will be compared to the baby gender afterbirth. Healthy third semester pregnant women were included as participants. Inform consent for both the mother and the biological father has been provided. Result : Four participants has been evaluated. In this study, in all participants, we found the presence of cffDNA in almost all of the STR loci. Some loci cannot be detected due to the small amount of cffDNA in the loci. All fetus genders detected by cffDNA in the amelogenin gene macthed the gender of the four babies afterbirth. Conclusion : The use of Cell-Free Fetal DNA (cffDNA) is a potential non-invasive methods in prenatal paternity test. Additionally, the ability of the method to evaluate fetus gender has been suggested.

Clinical characteristics and outcomes of pregnancy after invasive prenatal testing in women with multiple pregnancy

Retrospective assessment of the obstetric and gynecological history, gravidity, parity and complications of the current pregnancy in women who underwent amniocentesis (AC) and chorionic villus sampling (CVS) are presented. The features of invasive prenatal procedures (IPP), as well as the outcomes of pregnancy and childbirth were studied. The frequency of spontaneous abortion (SA) after AC was 2.90 ± 2.05%, during CVS — 2.80 ± 2.82%, in the comparison group (GC) (1.10 ± 1.07%, p &gt; 0.017). There were no statistically significant differences in invasive prenatal diagnostics in the 1st and 2nd trimesters in multiple and single pregnancies. AC and CVS do not affect the average delivery time (CVS — 37.0 (34.0–38.0) weeks, AC — 36.0 (34.0–38.0) weeks, GS — 36.0 (34.0–37.0) weeks, p &gt; 0.017), weight of newborns (CVH — 2440.0 (1960.0–2845.0) g, AC — 2600.0 (1850.0–2760.0) g, GS — 2325.0 (1800.0–2740.0) g, p &gt; 0.017). IPP do not increase the preterm birth rate at 23–36 weeks' gestation (CVH — 41.40 ± 9.15%, AC — 51.60 ± 6.36%, GS — 54.40 ± 5.19%, p &gt; 0.017) and does not increase perinatal mortality.

Attitude of women and their husbands regarding prenatal invasive testing attending genetic clinic at a tertiary referral center, India

Introduction: Prenatal Invasive Tests (amniocentesis and chorionic villous sampling) are used during pregnancy for detection of genetic anomalies. Due to the fear of fetal loss or various other reasons, the couples who seek to avail these tests areusually in dilemma though the chances of fetal loss following the invasive tests are very minimal.&#x0D; Objectives: To assess the attitude ofhigh-risk pregnantwomen and their husbands regarding the prenatal invasive tests who are referred to the genetic clinic of a tertiary referral center in India.&#x0D; Methodology: A descriptive, cross sectionalstudy was undertaken in 60 pregnantwomen who came to genetic clinic at a tertiary referral center in Indiafor counseling on the prenatal invasive testing. Conveniencesampling technique was used. Data was collected using a self-developed, validated semi structured questionnaire. There were total 14 items in the questionnaire where the response “Yes” was given score 3, “Uncertain/did not think about it” was given score 2 and “No” was given score 1. Maximum score was 42 and minimum was 14. The subjects were contacted by the principal investigator after the counseling for test was done by the trained counselor. The questionnaire was also administered separately to 49 accompanying husbands to assess their attitude regarding the tests. Mean, percentage, standard deviation, range and Pearson’s correlation were calculated.SPSS 16.0 version was used for data analysis.&#x0D; Results: Almost half of the women reported that they had adequate information regarding the test following counselling. Both the women and their husbands had unfavorable attitude towards the tests i.e. 21.98 ± 5.44 and 22.27 ± 5.11 respectively despite adequate information following counselling. The main reasons for declining the tests were fear of identification of birth defects, fear of termination of pregnancy and influence by other family membersother than their husbands. There was a significant positive correlation between the attitude of women and their husbands towards declining the prenatal invasive tests (r=0.973) at p&lt;0.05.&#x0D; Conclusion: The pregnant women as well as their husbands had unfavorable attitudes towards prenatal invasive tests despite adequate information following counsellingsuggesting congruency indecision makingregarding the invasive tests.

Screening for Aneuploidy in the Patient With Diabesity: Pearls and Pitfalls

The American College of Obstetrics & Gynecology (ACOG) recommends offering aneuploidy screening to all pregnant women. Obesity and diabetes are not associated with an increased risk of aneuploidy; however, they can complicate and compromise testing options. As the prevalence of obesity and diabetes, or "diabesity" increases, counseling women regarding potential limitations in testing performance of aneuploidy screening is of paramount importance. This chapter reviews options for aneuploidy screening for women with diabesity including sonography/nuchal translucency, serum analyte screening, and cell-free DNA. Potential challenges associated with diagnostic testing with amniocentesis and chorionic villus sampling in women with obesity are also discussed.

VP44.02: Risk of fetal loss following amniocentesis or chorionic villous sampling in twin pregnancies: a systematic review and meta‐analysis

VP44.02: Risk of fetal loss following amniocentesis or chorionic villous sampling in twin pregnancies: a systematic review and meta‐analysis

VP06.09: Procedure‐related risk of premature delivery and fetal growth reduction following amniocentesis, transcervical and transabdominal chorionic villus sampling: a retrospective study

VP06.09: Procedure‐related risk of premature delivery and fetal growth reduction following amniocentesis, transcervical and transabdominal chorionic villus sampling: a retrospective study

Invasive Prenatal Diagnosis

Despite recent advances in genetic technologies that are making invasive prenatal diagnosis less common, amniocentesis and chorionic villus sampling (CVS) remain an integral part of prenatal care. A multitude of tests, including a variety of genetic tests, can be performed using samples collected from either procedure. Although invasive testing has limitations, many genetic conditions can only be diagnosed through invasive techniques during pregnancy. Invasive testing continues to assist patients and providers in making informed decisions regarding the care of pregnancies. This review details amniocentesis and chorionic villus sampling with a focus on genetic testing, describing why the tests are performed, the way in which they are performed, and the associated limitations and complications of the procedures. This review 5 figures, 3 tables, and 26 references. Keywords: prenatal diagnosis, amniocentesis, chorionic villus sampling, genetic testing, genetic counseling, invasive prenatal testing, pregnancy, aneuploidy

Hirschsprung disease: Insights on genes, penetrance, and prenatal diagnosis.

The objective of this mini-review is to provide insights on the advances in the understanding of the genetic variants associated with different manifestations of Hirschsprung disease, which may present with a range of denervation from a short segment of colon to total colonic and small bowel or extensive aganglionosis. A recent article in this journal documented potential gene variants involved in long-segment Hirschsprung disease in 23 patients. Gene variants were identified using a 31-gene panel of genes related to Hirschsprung disease or enteric neural crest cell development, as previously reported in the literature. The study identified potentially harmful variants in eight genes across 13 patients, with a detection rate of 56.5% (13/23 patients). Five patients had pathologic variants in RET, NRG1, and L1CAM, and the remainder were considered variants of unknown significance. The authors attempted prenatal diagnosis of Hirschsprung disease utilizing an amniocentesis sample obtained for advanced maternal age in a family with a known deleterious RET mutation, manifested in the father (long-segment Hirschsprung disease) and older daughter (total colonic aganglionosis). The fetus had the same RET variant but, after several years of follow-up, has not developed any symptoms of Hirschsprung disease, supporting the conclusion that this RET mutation is an autosomal dominant gene with incomplete penetrance. This experience suggests that genetic counseling is appropriate to carefully assess the justification of prenatal testing, especially, when the phenotype of long-segment Hirschsprung disease is so variable and the disease is potentially curable with surgery.

Angiotensin II and TGF-β1 Induce Alterations in Human Amniotic Fluid-Derived Mesenchymal Stem Cells Leading to Cardiomyogenic Differentiation Initiation.

Background and ObjectivesHuman amniotic fluid-derived mesenchymal stem cells (AF-MSCs) may be a valuable source for cardiovascular tissue engineering and cell therapy. The aim of this study is to verify angiotensin II and transforming growth factor-beta 1 (TGF-β1) as potential cardiomyogenic differentiation inducers of AF-MSCs.Methods and ResultsAF-MSCs were obtained from amniocentesis samples from second-trimester pregnant women, isolated and characterized by the expression of cell surface markers (CD44, CD90, CD105 positive; CD34 negative) and pluripotency genes (OCT4, SOX2, NANOG, REX1). Cardiomyogenic differentiation was induced using different concentrations of angiotensin II and TGF-β1. Successful initiation of differentiation was confirmed by alterations in cell morphology, upregulation of cardiac genes-markers NKX2-5, TBX5, GATA4, MYH6, TNNT2, DES and main cardiac ion channels genes (sodium, calcium, potassium) as determined by RT-qPCR. Western blot and immunofluorescence analysis revealed the increased expression of Connexin43, the main component of gap junctions, and Nkx2.5, the early cardiac transcription factor. Induced AF-MSCs switched their phenotype towards more energetic and started utilizing oxidative phosphorylation more than glycolysis for energy production as assessed using Agilent Seahorse XF analyzer. The immune analysis of chromatin-modifying enzymes DNMT1, HDAC1/2 and Polycomb repressive complex 1 and 2 (PRC1/2) proteins BMI1, EZH2 and SUZ12 as well as of modified histones H3 and H4 indicated global chromatin remodeling during the induced differentiation.ConclusionsAngiotensin II and TGF-β1 are efficient cardiomyogenic inducers of human AF-MSCs; they initiate alterations at the gene and protein expression, metabolic and epigenetic levels in stem cells leading towards cardiomyocyte-like phenotype formation.

P19.02: Procedural and obstetrical outcomes of amniocentesis or chorionic villus sampling in dichorionic twin pregnancies

P19.02: Procedural and obstetrical outcomes of amniocentesis or chorionic villus sampling in dichorionic twin pregnancies

Prenatal Screening and Diagnosis

Prenatal genetic testing offers patients and providers the opportunity to screen for aneuploidy, genetic syndromes, and congenital malformations during pregnancy. Screening options include taking a clinical history, evaluation of maternal serum markers or noninvasive cell-free DNA, and ultrasound evaluation during the first and second trimesters. Invasive diagnostic testing such as amniocentesis or chorionic villus sampling allows for further investigation of positive screening results and a directed test to identify aneuploidy as well as specific gene mutations and gain, loss, or rearrangement of genetic information. Laboratory methods for testing fetal samples differ by types of genetic abnormalities that can be detected and turnaround time for results; these methods include karyotype, fluorescence in situ hybridization, and microarray. This review contains 5 figures, 5 tables and 43 references Key words: amniocentesis, aneuploidy, cell-free DNA, chorionic villus sampling, karyotype, microarray, prenatal genetic screening, ultrasonography