Clinical impact of additional findings detected by genome-wide non-invasive prenatal testing: Follow-up results of the TRIDENT-2 study.

In the TRIDENT-2 study, all pregnant women in the Netherlands are offered genome-wide non-invasive prenatal testing (GW-NIPT) with a choice of receiving either full screening or screening solely for common trisomies. Previous data showed that GW-NIPT can reliably detect common trisomies in the general obstetric population and that this test can also detect other chromosomal abnormalities (additional findings). However, evidence regarding the clinical impact of screening for additional findings is lacking. Therefore, we present follow-up results of the TRIDENT-2 study to determine this clinical impact based on the laboratory and perinatal outcomes of cases with additional findings. Between April 2017 and April 2019, additional findings were detected in 402/110,739 pregnancies (0.36%). For 358 cases, the origin was proven to be either fetal (n = 79; 22.1%), (assumed) confined placental mosaicism (CPM) (n = 189; 52.8%), or maternal (n = 90; 25.1%). For the remaining 44 (10.9%), the origin of the aberration could not be determined. Most fetal chromosomal aberrations were pathogenic and associated with severe clinical phenotypes (61/79; 77.2%). For CPM cases, occurrence of pre-eclampsia (8.5% [16/189] vs 0.5% [754/159,924]; RR 18.5), and birth weight <2.3rd percentile (13.6% [24/177] vs 2.5% [3,892/155,491]; RR 5.5) were significantly increased compared to the general obstetric population. Of the 90 maternal findings, 12 (13.3%) were malignancies and 32 (35.6%) (mosaic) pathogenic copy number variants, mostly associated with mild or no clinical phenotypes. Data from this large cohort study provide crucial information for deciding if and how to implement GW-NIPT in screening programs. Additionally, these data can inform the challenging interpretation, counseling, and follow-up of additional findings.

Feasibility for non-invasive prenatal fetal blood group and platelet genotyping by massively parallel sequencing: A single test system for multiple atypical red cell, platelet and quality control markers.

Non-invasive prenatal tests (NIPT) to predict fetal red cell or platelet antigen status for alloimmunised women are provided for select antigens. This study reports on massively parallel sequencing (MPS) using a red cell and platelet probe panel targeting multiple nucleotide variants, plus individual identification single nucleotide polymorphisms (IISNPs). Maternal blood samples were provided from 33 alloimmunised cases, including seven with two red cell antibodies. Cell-free and genomic DNA was sequenced using targeted MPS and bioinformatically analysed using low-frequency variant detection. The resulting maternal genomic DNA allele frequency was subtracted from the cell-free DNA counterpart. Outcomes were matched against validated phenotyping/genotyping methods, where available. A 2.5% subtractive allele frequency threshold was set after comparing MPS predictions for K, RhC/c, RhE/e and Fya /Fyb against expected outcomes. This threshold was used for subsequent predictions, including HPA-15a, Jka /Jkb , Kpa /Kpb and Lua . MPS outcomes were 97.2% concordant with validated methods; one RhC case was discordantly negative and lacked IISNPs. IISNPs were informative for 30/33 cases as controls. NIPT MPS is feasible for fetal blood group genotyping and covers multiple blood groups and control targets in a single test. Noting caution for the Rh system, this has the potential to provide a personalised service for alloimmunised women.

The use of free DNA for fetal RHD genotyping in the Rh negative pregnant patient-the time has come.

Cell-free DNA to determine the fetal RHD genotype from the maternal circulation was first described in 1993. High throughput assays using polymerase chain reaction technology were introduced in Europe and gained widespread acceptance in the management of the Rhesus alloimmunized pregnancy. The specificity and sensitivity of these assays approached 99%. As confidence was gained with these results, Scandinavian countries began to employ cell-free DNA for fetal RHD typing as an integral component of their introduction of antenatal Rhesus immune globulin in non-alloimmunized pregnancies. Since 40% of RhD-negative pregnant women will carry an RhD-negative fetus, doses of Rhesus immune globulin were conserved. Recently 2 U.S. companies have introduced cell-free DNA assays for RHD as part of their noninvasive prenatal testing assays. Both utilize next generation sequencing and have developed methodologies to detect the aberrant RHD pseudogene and the hybrid RHD-CE-Ds genotype. In addition, excellent correlation studies with either neonatal genotyping or serology have been reported. The manufacturer of RhoGAM has recently announced a national shortage. Given the current availability of reliable cell-free DNA assays for determining the RHD status of the fetus, the time has come to implement this strategy to triage the antenatal use of Rhesus immune globulin in the U.S.

Uterine fibroids and non-informative cell-free DNA screening results.

OBJECTIVE: Uterine fibroids are monoclonal tumors, which are often genetically abnormal and associated with false-positive genome-wide cell-free DNA (cfDNA) screening results, particularly when large. It is plausible that fibroids may also increase the risk of cfDNA failure by affecting fetal fraction or due to their genetic anomalies confounding cfDNA algorithms. We aimed to investigate a possible association between fibroids and cfDNA non-informative results. METHODS: This was a retrospective cohort study of women undergoing cfDNA screening for fetal chromosomal abnormalities between 2013 and 2020, comparing pregnancies with vs without uterine fibroids recorded on any obstetric ultrasound before 24 weeks' gestation. Univariable and multivariable logistic regression models were used to investigate the association between fibroids and cfDNA failure, adjusting for gestational age, maternal age, weight and height at blood sampling, mode of conception, multiple gestation and test platform (chromosome-selective or genome-wide). Analyses were stratified according to the number of fibroids and total fibroid volume. The impact of fibroids on fetal fraction was assessed using linear regression, adjusting for the same covariates. RESULTS: Among 19 818 pregnancies undergoing cfDNA screening, fibroids were reported in 2038 (10.28%) and cfDNA failure at the first screening attempt occurred in 228 (1.15%) pregnancies. Non-informative results occurred in 1.96% of pregnancies with fibroids and 1.06% of pregnancies without fibroids (adjusted odds ratio (aOR), 2.40 (95% CI, 1.65-3.48)). The risk of failure in the first screening attempt increased progressively with the number of fibroids (aOR, 5.05 (95% CI, 2.29-11.13) in women with four or more fibroids) and total fibroid volume, with greater than a 5-fold and 14-fold increase in risk among women with fibroid volumes of 100.1-400 mL (aOR, 5.52 (95% CI, 2.30-13.25)) and > 400 mL (aOR, 14.80 (95% CI, 4.50-48.69)), respectively. Although test failure was more common with chromosome-selective than genome-wide screening, fibroids similarly increased the risk of failure of both screening platforms. Compared to pregnancies without fibroids, those with fibroids had a fetal fraction on average 0.61% lower (adjusted mean difference, -0.61% (95% CI, -0.77% to -0.45%)). CONCLUSION: Uterine fibroids are associated with lower fetal fraction and an increased risk of cfDNA screening failure. The strength of this association increases with increasing fibroid number and volume. © 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Combined first-trimester screening and invasive diagnostics for atypical chromosomal aberrations: Danish nationwide study of prenatal profiles and detection compared with NIPT.

OBJECTIVES: Our aim was to examine the prenatal profiles of pregnancies affected by an atypical chromosomal aberration, focusing on pathogenic copy-number variants (pCNVs). We also wanted to quantify the performance of combined first-trimester screening (cFTS) and a second-trimester anomaly scan in detecting these aberrations. Finally, we aimed to estimate the consequences of a policy of using non-invasive prenatal testing (NIPT) rather than invasive testing with chromosomal microarray analysis (CMA) to manage pregnancies identified as high risk by cFTS. METHODS: This was a retrospective review of the Danish Fetal Medicine Database of all pregnant women who underwent cFTS and a risk assessment for trisomy 21 between 1 January 2008 and 31 December 2018. Chromosomal aberrations diagnosed prenatally, postnatally or from fetal tissue following pregnancy loss or termination of pregnancy were identified. Chromosomal aberrations were grouped into one of six categories: triploidy; common trisomy (13, 18 or 21); monosomy X; other sex-chromosome aberration (SCA); pCNV; and rare autosomal trisomy (RAT) or mosaicism. The prevalence of each aberration category was stratified by the individual cFTS markers and trisomy 21 risk estimate, and the size of each pCNV diagnosed by CMA was calculated. RESULTS: We retrieved data on 565 708 pregnancies, of which 3982 (0.70%) were diagnosed with a fetal chromosomal aberration. cFTS identified 87% of the common trisomies, but it also performed well in identifying triploidies (86%), monosomy X (92%), atypical SCAs (58%) and RATs or mosaicisms (70%). pCNVs comprised 27% (n = 1091) of the chromosomal aberrations diagnosed overall, and the prevalence increased during the study period, as prenatal CMA was increasingly being performed. In pregnancies with a maternal age < 30 years, nuchal translucency (NT) thickness ≤ 95th centile, pregnancy-associated plasma protein-A (PAPP-A) ≥ 1 multiple of the median, or trisomy 21 risk of ≤ 1 in 1000, the prevalence of pCNVs exceeded significantly the prevalence of trisomies 21, 18 and 13. Pregnancies affected by a pCNV had significantly increased NT and decreased levels of the maternal biomarkers PAPP-A and ß-human chorionic gonadotropin compared with unaffected pregnancies. However, only 23% of these pregnancies screened positive on cFTS and 51% of pCNVs were not detected until after birth. Among high-risk pregnancies, pCNVs comprised 14% of diagnosed aberrations, and when other atypical aberrations were considered, conventional NIPT (screening for trisomies 21, 18 and 13 and monosomy X) would miss 27% of all pathogenic aberrations diagnosed from invasive testing following a high-risk cFTS result. Thus, 1 in 26 pregnancies at high risk following cFTS would be affected by a chromosomal aberration despite a normal result from conventional NIPT. In a contingent screening model using NIPT for the 'intermediate'-risk group (trisomy 21 risk of 1 in 100-299), 50% of the aberrations would be missed. In our cohort, 79% of the pCNVs diagnosed were < 5Mb and therefore not detectable using current forms of 'genome-wide' NIPT. CONCLUSIONS: As a by-product of screening for trisomies 21, 18 and 13, most triploidies and the majority of atypical SCAs, RATs and mosaicisms are detected before birth. However, only 23% of pCNVs are associated with a high-risk result according to cFTS and only half are diagnosed before birth. Replacing invasive testing with NIPT for high-risk pregnancies would substantially decrease the first-trimester detection of pathogenic chromosomal anomalies. © 2024 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

The efficacy of expanded non-invasive prenatal testing (NIPT) in a high-risk twin pregnancies cohort.

INTRODUCTION: Our objective was to evaluate the efficacy of expanded non-invasive prenatal testing (NIPT) that includes both trisomies and copy number variants (CNVs) in high-risk twin pregnancies. MATERIAL AND METHODS: A prospective, double-blinded cohort study was conducted, enrolling 73 high-risk twin pregnancies characterized by increased risk of genetic disorders due to factors such as increased nuchal translucency, structural anomalies, fetal growth restriction, and other factors associated with chromosomal abnormality. Participants underwent invasive karyotyping and chromosomal microarray analysis, alongside separate expanded NIPT for research purposes. The sensitivity, specificity, positive predictive value, and negative predictive value of expanded NIPT were calculated. RESULTS: The cohort included 24 monochorionic and 49 dichorionic twin pregnancies. The median cell-free fetal DNA concentration in expanded NIPT was 16.7% (range 3.86%-49.1%), with a test failure rate of 1.4% (1/73). High-risk findings for trisomy 21/13/18 were identified in five cases (6.8%), Turner syndrome in one case (1.4%), and CNVs indicative of high risk for clinically significant microdeletion/microduplication syndromes (MMS) in ten cases (13.7%). Of these, 56 cases (76.7%) tested NIPT negative, revealing one false-negative for 45, X and five false-negatives for CNVs. Expanded NIPT achieved a detection rate of 100% (5/5) for trisomy 21/13/18 with a false-positive rate of 0% (0/5), a detection rate of 33.3% (1/3) for sex chromosome abnormalities with a false-positive rate of 0% (0/3), and a detection rate of 66.7% (4/6) for MMS with a false-positive rate of 3.0% (2/67). The positive predictive values for trisomy T21/13/18, sex chromosome abnormalities, and known MMS were 100% (5/5), 100% (1/1), and 66.7% (4/6) in the expanded NIPT, respectively. CONCLUSIONS: The expanded NIPT demonstrated high detection rates for common trisomies and moderate detection rates for prenatal MMS in high-risk twin pregnancies. Further studies with large sample sizes in low-risk populations are needed.

NIPT for adult-onset conditions: Australian NIPT users' views.

Noninvasive prenatal testing (NIPT) has become widely available in recent years. While initially used to screen for trisomies 21, 18, and 13, the test has expanded to include a range of other conditions and will likely expand further. This paper addresses the ethical issues that arise from one particularly controversial potential use of NIPT: screening for adult-onset conditions (AOCs). We report data from our quantitative survey of Australian NIPT users' views on the ethical issues raised by NIPT for AOCs. The survey ascertained support for NIPT for several traits and conditions including AOCs. Participants were then asked about their level of concern around implications of screening for AOCs for the future child and parent(s). Descriptive and comparative data analyses were conducted. In total, 109 respondents were included in data analysis. The majority of respondents expressed support for NIPT screening for preventable (70.9%) and nonpreventable AOCs (80.8%). Most respondents indicated concern around potential harmful impacts associated with NIPT for AOCs, including the psychological impact on the future child and on the parent(s). Despite this, the majority of participants thought that continuation of a pregnancy known to be predisposed to an AOC is ethically acceptable. The implications of these data are critically discussed and used to inform the normative claim that prospective parents should be given access to NIPT for AOCs. The study contributes to a body of research debating the ethical acceptability and regulation of various applications of NIPT as screening panels expand.

Antenatal RHD screening to guide antenatal anti-D immunoprophylaxis in non-immunized D- pregnant women.

In pregnancy, D- pregnant women may be at risk of becoming immunized against D when carrying a D+ fetus, which may eventually lead to hemolytic disease of the fetus and newborn. Administrating antenatal and postnatal anti-D immunoglobulin prophylaxis decreases the risk of immunization substantially. Noninvasive fetal RHD genotyping, based on testing cell-free DNA extracted from maternal plasma, offers a reliable tool to predict the fetal RhD phenotype during pregnancy. Used as a screening program, antenatal RHD screening can guide the administration of antenatal prophylaxis in non-immunized D- pregnant women so that unnecessary prophylaxis is avoided in those women who carry a D- fetus. In Europe, antenatal RHD screening programs have been running since 2009, demonstrating high test accuracies and program feasibility. In this review, an overview is provided of current state-of-the-art antenatal RHD screening, which includes discussions on the rationale for its implementation, methodology, detection strategies, and test performance. The performance of antenatal RHD screening in a routine setting is characterized by high accuracy, with a high diagnostic sensitivity of ≥99.9 percent. The result of using antenatal RHD screening is that 97-99 percent of the women who carry a D- fetus avoid unnecessary prophylaxis. As such, this activity contributes to avoiding unnecessary treatment and saves valuable anti-D immunoglobulin, which has a shortage worldwide. The main challenges for a reliable noninvasive fetal RHD genotyping assay are low cell-free DNA levels, the genetics of the Rh blood group system, and choosing an appropriate detection strategy for an admixed population. In many parts of the world, however, the main challenge is to improve the basic care for D- pregnant women.

Impact of the new government-involved noninvasive prenatal testing certification system on the awareness of pregnant women about noninvasive prenatal testing in Japan.

AIM: In Japan, noninvasive prenatal testing (NIPT) has been performed by facilities accredited by the Japanese Society of Obstetrics and Gynecology since 2013. However, since 2016, with the implementation of NIPT, which can only be performed by blood sampling, non-obstetricians have been involved in prenatal testing. Therefore, in July 2022, a new government-involved NIPT certification system based on Health Sciences Council guidelines was introduced to ensure access to prenatal testing information for pregnant women. METHODS: This survey was conducted in February 2023 and was the first survey after the certification system implementation. We conducted a web-based survey of 1227 pregnant women and nursing mothers who underwent NIPT after July 2022 to evaluate their experiences. RESULTS: Respondents were categorized by certification status as certified (C: 56%), non-certified (non-C: 23%), or uncertain (Q: 20%). The C group with a higher mean age at examination (35.0 ± 4.5 years) paid lower examination fees, received longer pre- and post-examination explanations, and underwent more weekday examinations (80%) than the other groups. Most respondents, 67%, 48%, and 53% in the C, non-C, and Q groups, respectively (p < 0.0001), stated that "NIPT needs to be regulated by the government or academic societies." The non-C group was more likely to say, "Insufficient post-test explanations at the laboratory made me more anxious," than the other groups when the testing results were non-negative (p = 0.015). CONCLUSIONS: Despite government regulation, some pregnant women choose convenience over certified facilities, risking inadequate care. The government should ensure that NIPT is a safe option for all pregnant women.

Low fetal fraction and adverse pregnancy outcomes- systematic review of the literature and metanalysis.

PURPOSE: While cell-free DNA (cfDNA) screening has emerged as a screening modality for common aneuploidies, further research and several publications over the past decade suggested some correlation between the low concentrations of cfDNA and a number of pregnancy-related complications. The primary goal of this systematic review and meta-analysis was to assess the potential value of low-ff levels in the prediction of subsequent PE/PIH, GDM, SGA/FGR, and PTB. The meta-analysis results aim at summarizing the currently available literature data and determining the clinical relevance of this biochemical marker and the potential necessity for additional investigation of its utility in complications other than the detection of common aneuploidies. METHODS: This systematic review and meta-analysis was designed according to the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. It included all observational studies that reported low -ff levels after the performance of non-invasive prenatal testing (NIPT) as part of the screening for chromosomal abnormalities and their association with adverse pregnancy outcomes, namely the subsequent development of hypertensive disorders of pregnancy, gestational diabetes, preterm birth, and the detection of small for gestational age fetuses or growth-restricted fetuses. The Medline (1966-2041), Scopus (2004-2024), Clinicaltrials.gov (2008-2024), EMBASE (1980-2024), Cochrane Central Register of Controlled Trials CENTRAL (1999-2024) and Google Scholar (2004-2024) databases were used in our primary search along with the reference lists of electronically retrieved full-text papers. The date of our last search was set at February 29, 2024. RESULTS: Our search identified 128 potentially relevant studies and,overall, 8 studies were included in the present systematic review that enrolled a total of 72,507 patients. Low ff of cfDNA cfDNA was positively associated with HDP (OR 1.66, 95% CI 1.34, 2.06, I-square test: 56%). Low ff of cfDNA was positively associated with GDM (OR 1.27, 95% CI 1.03, 1.56, I-square test: 76%). Furthermore, low ff levels were positively associated with SGA/FGR (OR 1.63, 95% CI 1.32, 2.03, I-square test: 0%). Low ff levels were positively correlated with the risk for PTB but the association did not manage to reach a statistical significant level (OR 1.22, 95% CI 0.89, 1.67, I-square test: 66%). CONCLUSION: Our study suggests that low ff is associated with increased risk of adverse perinatal outcomes, including PE/PIH, GDM, and SGA/FGR. However, the relationship between ff and PTB remains unclear due to conflicting evidence. It should be emphasized that further research is needed to reveal the underlying mechanisms behind the association of low ff with adverse pregnancy outcomes and explore its potential role in an overall prenatal screening, which could potentially not be limited to detecting aneuploidies.

Prenatal and postnatal genetic testing toward personalized care: The non-invasive perinatal testing.

This article investigates how non-invasive prenatal testing and the incorporation of genomic sequencing into newborn screening postnatally are transforming perinatal care. They improve the accuracy of prenatal and neonatal screening, allowing for early interventions and personalized therapies. Non-invasive prenatal testing before birth and saliva-sample-based newborn genomic sequencing after birth can be collectively referred to as non-invasive perinatal testing. Non-invasive prenatal testing is particularly useful for aneuploidy, whereas performance markers worsen as DNA abnormalities shrink in size. Screening for clinically actionable diseases in childhood would be crucial to personalized medical therapy, as the postnatal period remains appropriate for screening for the great majority of monogenic disorders. While genomic data can help diagnose uncommon diseases, challenges like ethics and equity necessitate joint approaches for appropriate integration in this revolutionary journey toward personalized care.

A new and improved method of library preparation for non-invasive prenatal testing: plasma to library express technology.

OBJECTIVES: This study aims to develop a novel library preparation method, plasma to library express technology (PLET), to construct next-generation sequencing (NGS) libraries directly from plasma without cell-free DNA (cfDNA) isolation. METHODS: Peripheral blood samples (600) were obtained from a retrospective cohort of 300 pregnant women prior to invasive diagnostic testing. The samples were subsequently distributed between library preparation methodologies, with 300 samples prepared by PLET and 300 by conventional methods for non-invasive prenatal testing (NIPT) to screen for common trisomies using low-pass whole genome next generation sequencing. RESULTS: NIPT conducted on PLET libraries demonstrated comparable metrics to libraries prepared using conventional methods, including 100% sensitivity and specificity. CONCLUSIONS: Our study demonstrates the potential utility of PLET in the clinical setting and highlights its significant advantages, including dramatically reduced process complexity and markedly decreased turnaround time.

Late first-trimester ultrasound findings can alter management after high-risk NIPT result.

OBJECTIVE: To evaluate the impact of detailed late first-trimester ultrasound (LFTU) on the positive predictive value (PPV) of a high-risk non-invasive prenatal test (NIPT) result for various chromosomal abnormalities. METHODS: This was a retrospective study of all cases undergoing invasive prenatal testing from three tertiary providers of obstetric ultrasound over 4 years, each using NIPT as a first-line screening test. Data were collected from pre-NIPT ultrasound, NIPT, LFTU, placental serology and later ultrasound examinations. Prenatal testing for chromosomal abnormalities was performed by microarray, initially using array comparative genomic hybridization and then single nucleotide polymorphism (SNP) array for the last 2 years. Uniparental disomy testing was performed by SNP array during all 4 years. The majority of NIPT tests were analyzed using the Illumina platform, initially confined to the assessment of the common autosomal trisomies, sex chromosome aneuploidies and rare autosomal trisomies (RAT), then extending to genome-wide analysis for the last 2 years. RESULTS: Amniocentesis or chorionic villus sampling (CVS) was performed on 2657 patients, 1352 (51%) of whom had undergone prior NIPT, with 612 (45%) of these returning a high-risk result and meeting the inclusion criteria for the study. LFTU findings significantly affected the PPV of the NIPT result for trisomies 13 (T13), 18 (T18) and 21 (T21), monosomy X (MX) and RAT but not for the other sex chromosomal abnormalities or segmental imbalances (> 7 Mb). Abnormal LFTU increased the PPV close to 100% for T13, T18, T21, MX and RAT. The magnitude of the change in PPV was highest for the most severe chromosomal abnormalities. When LFTU was normal, the incidence of confined placental mosaicism (CPM) was highest in those with a high-risk NIPT result for T13, followed by T18 and T21. After normal LFTU, the PPV for T21, T18, T13 and MX decreased to 68%, 57%, 5% and 25%, respectively. CONCLUSIONS: LFTU after a high-risk NIPT result can alter the PPV for many chromosomal abnormalities, assisting counseling regarding invasive prenatal testing and pregnancy management. The high PPVs of NIPT for T21 and T18 are not sufficiently modified by normal LFTU findings to alter management. These at-risk patients should be offered CVS for earlier diagnosis, particularly given the low rate of CPM associated with these aneuploidies. Patients with a high-risk NIPT result for T13 and normal LFTU findings often wait for amniocentesis or avoid invasive testing altogether given the low PPV and higher rate of CPM in this context. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Non-invasive cell-free DNA prenatal screening for trisomy 21 as part of primary screening strategy in twin pregnancies.

OBJECTIVES: The performance of non-invasive prenatal screening using cell-free DNA testing in maternal blood in twin pregnancies is still under-evaluated, while serum marker-based strategies yield poor results. This study aims at assessing the performance of non-invasive prenatal screening for trisomy 21 in twin pregnancies as a first-tier test. The secondary objectives were to assess the failure rate and associated factors. METHODS: This retrospective cohort study included twin pregnancies for which non-invasive prenatal screening using cell-free DNA was performed as the primary screening strategy between May 2017 and October 2019. We used the NIPT VeriSeq® test for in vitro diagnosis and set a fetal fraction cut-off of 4% for monochorionic pregnancies and 8% for dichorionic ones. Clinical data and pregnancy outcome was collected from either physicians or midwives through a questionnaire or were retrieved directly on site. We calculated the performance of non-invasive cell free DNA screening for trisomy 21 and analyzed failure rate and factors. RESULTS: We included 2577 multiple pregnancies among which 1885 (84.8%) were retained after excluding vanishing twins and pregnancies without follow-up. Overall, there were six confirmed trisomy 21 cases (0.32%). For trisomy 21, sensitivity was 100% (95% CI, 61-100%) and the false-positive rate 0.2% (95% CI, 0.07-0.6%). The primary failure rate was 4.6% with 4% due to insufficient fetal fraction. After a new blood draw (59.8% of failed cases), failure rate was only 1.5%. Body mass index and chorionicity were significantly correlated with the risk of failure. CONCLUSION: This study adds further evidence on the high performance of NIPS in twins, as part of the primary screening strategy for trisomy 21, at an extremely low false-positive rate. This article is protected by copyright. All rights reserved.

Incidence of sex chromosome aneuploidy in a prenatal population: 27-year longitudinal study in Northern Italy.

OBJECTIVES: The availability of cell-free (cf) DNA as a prenatal screening tool affords an opportunity for non-invasive identification of sex chromosome aneuploidy (SCA). The aims of this longitudinal study were to investigate the evolution and frequency of both invasive prenatal diagnostic testing, using amniocentesis and chorionic villus sampling (CVS), and the detection of SCA in cfDNA samples from a large unselected cohort in Northern Italy. METHODS: The results of genetic testing from CVS and amniotic fluid samples received from public and private centers in Italy from 1995 to 2021 were collected. Chromosomal analysis was performed by routine Q-banding karyotype. Regression analyses and descriptive statistics were used to determine population data trends regarding the frequency of prenatal diagnostic testing and the identification of SCA, and these were compared with the changes in indication for prenatal diagnostic tests and available screening options. RESULTS: Over a period of 27 years, there were 13 939 526 recorded births and 231 227 invasive procedures were performed, resulting in the prenatal diagnosis of 933 SCAs. After the commercial introduction of cfDNA use in 2015, the frequency of invasive procedures decreased significantly (P = 0.03), while the frequency of prenatal SCA detection increased significantly (P = 0.007). Between 2016 and 2021, a high-risk cfDNA result was the indication for 31.4% of detected sex chromosome trisomies, second only to advanced maternal age. CONCLUSIONS: Our findings suggest that the inclusion of SCA in prenatal cfDNA screening tests can increase the prenatal diagnosis of affected individuals. As the benefits of early ascertainment are increasingly recognized, it is essential that healthcare providers are equipped with comprehensive and evidence-based information regarding the associated phenotypic differences and the availability of targeted effective interventions to improve neurodevelopmental and health outcomes for affected individuals. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Trophoblast retrieval from the cervical canal to predict abnormal pregnancy early in gestation: a pilot study.

BACKGROUND: The current detection of fetal chromosomal abnormalities by non-invasive prenatal testing (NIPT) mainly relies on the cell free DNA(cfDNA) in the maternal blood. However, a gestational age of less than 12 weeks or a high maternal BMI affects cfDNA fetal fraction and further the detection by NIPT negatively. In this study, we aim to retrieve the trophoblast cells from the maternal cervix to develop a new sampling method for NIPT enabling an earlier use of NIPT. METHODS: We enrolled three patients who wanted to undergo induced abortion at Beijing Hospital between January 2022 and March 2022. Peripheral blood, cervix specimen, and the abortion tissue were collected and processed for each patient. Allele frequencies of the mutated gene loci of the maternal blood and the cervix sample were compared and the Sex Determining Region Y (SRY) gene was tested. RESULTS: The allele frequencies of the mutated gene loci showed no significant difference between the maternal blood and the cervix sample. But we successfully detected signal of the SRY gene in the cervix sample of the only patient carrying a male fetus. CONCLUSIONS: The detection of the SRY gene in a cervix sample indicated a successful retrieval of trophoblast cells from the cervix canal. Further study needs to be conducted to verify our finding before its application to the clinical settings.

Association of maternal risk factors with fetal aneuploidy and the accuracy of prenatal aneuploidy screening: a correlation analysis based on 12,186 karyotype reports.

BACKGROUND: NIPT is becoming increasingly important as its use becomes more widespread in China. More details are urgently needed on the correlation between maternal risk factors and fetal aneuploidy, and how these factors affect the accuracy of prenatal aneuploidy screening. METHODS: Information on the pregnant women was collected, including maternal age, gestational age, specific medical history and results of prenatal aneuploidy screening. Additionally, the OR, validity and predictive value were also calculated. RESULTS: A total of 12,186 analysable karyotype reports were collected with 372 (3.05%) fetal aneuploidies, including 161 (1.32%) T21, 81 (0.66%) T18, 41 (0.34%) T13 and 89 (0.73%) SCAs. The OR was highest for maternal age less than 20 years (6.65), followed by over 40 years (3.59) and 35-39 years (2.48). T13 (16.95) and T18 (9.40) were more frequent in the over-40 group (P < 0.01); T13 (3.62/5.76) and SCAs (2.49/3.95) in the 35-39 group (P < 0.01). Cases with a history of fetal malformation had the highest OR (35.94), followed by RSA (13.08): the former was more likely to have T13 (50.65) (P < 0.01) and the latter more likely to have T18 (20.50) (P < 0.01). The sensitivity of primary screening was 73.24% and the NPV was 98.23%. The TPR for NIPT was 100.00% and the respective PPVs for T21, T18, T13 and SCAs were 89.92, 69.77, 53.49 and 43.24%, respectively. The accuracy of NIPT increased with increasing gestational age (0.81). In contrast, the accuracy of NIPT decreased with maternal age (1.12) and IVF-ET history (4.15). CONCLUSIONS: ①Pregnant patients with maternal age below 20 years had higher risk of aneuploidy, especially in T13; ②A history of fetal malformations is more risky than RSA, with the former more likely to have T13 and the latter more likely to have T18; ③Primary screening essentially achieves the goal of identifying a normal karyotype, and NIPT can accurately screen for fetal aneuploidy; ④A number of maternal risk factors may influence the accuracy of NIPT diagnosis, including older age, premature testing, or a history of IVF-ET. In conclusion, this study provides a reliable theoretical basis for optimizing prenatal aneuploidy screening strategies and improving population quality.

Patient perspectives on noninvasive prenatal testing among black women in the United States: a scoping review.

Advances in reproductive health technologies such as noninvasive prenatal testing (NIPT) are changing the landscape of prenatal care and maternal health. NIPT, made clinically available in the United States (US) in 2011, is a screening test that utilizes cell-free DNA (cfDNA) to detect for aneuploidies and genetic characteristics in fetal DNA. In September 2020, the American College of Obstetricians and Gynecologists (ACOG) recommended NIPT for all pregnant patients regardless of age or risk factors. We examined peer-reviewed, empirical studies published from January 2011 to February 2022, assessing NIPT studies with patient perspectives in the US and what is known about how empirical studies include Black women. Our scoping review draws from PubMed (with advanced MeSH search options) and Scopus databases for advanced scoping review, with 33 articles meeting our criteria. Empirical studies on NIPT show patient perceptions range across five themes: 1) accuracy / safety, 2) return of results, 3) patient knowledge, 4) informed consent, and 5) perceptions among minoritized groups (with perceptions of race and gender as a social demographic intersection). Additionally, among the 15 studies that included that Black woman in their study sample, none measured the perceptions of Black women with genetic conditions. Bridging this knowledge gap is critical because NIPT is becoming increasingly accessible across the nation and is being developed to screen for additional genetic conditions, such as sickle cell disease. Ultimately, NIPT researchers need to go to greater lengths to examine the patient perspectives of Black women with and without genetic conditions.

Effects of an animated educational video on knowledge of cell-free DNA screening among Thai pregnant women: a randomized control trial.

BACKGROUND: In developing countries, pregnant women have insufficient knowledge about cell-free DNA screening. Reports from developed countries have found that various tools in prenatal genetic counseling can improve the knowledge of pregnant women who undergo cell-free DNA screening. Data are limited from developing countries where women have different baseline socio-educational backgrounds. The objective of this study was to compare the effects of an animated educational video combined with traditional counseling versus traditional counseling alone in changing pregnant women's knowledge of cell-free DNA screening. METHODS: This study was a randomized control trial at an antenatal clinic. Eligible subjects who were Thai pregnant women, were randomized to either view or not view the 4-minute animated educational video explaining cell-free DNA screening. Both groups received traditional counseling. The women were asked to complete a Thai questionnaire assessing knowledge of the screening before and after intervention. The questionnaire consisted of three sections: demographic data of the research participants and their existing awareness about cell-free DNA testing; performance and limitations of cell-free DNA screening; and participants' attitudes toward the positive screening. Primary outcome was the change in knowledge scores. Secondary outcomes were attitudes toward positive screening test, levels of satisfaction with counseling, and screening acceptance rates. RESULTS: Data from 83 women in the video group and 82 in the non-video group were analyzed. The knowledge score (range 0-18) change after counseling was significantly higher in the video group than the non-video group (+ 7.1 ± 3.3 vs + 4.2 ± 2.5; p = 0.03). There were no significant differences in attitudes toward positive screening test (p = 0.83), levels of satisfaction (p = 0.24), or screening acceptance rates (p = 0.15) between the groups. CONCLUSIONS: Adding the video to traditional counseling was better than traditional counseling alone in improving pregnant women's knowledge about cell-free DNA screening. TRIAL REGISTRATION: The study was retrospectively registered with the Thai Clinical Trials Registry (TCTR20210917001, 17/09/2021).

Detecting mitochondrial mutations associated with aminoglycoside ototoxicity by noninvasive prenatal testing.

OBJECTIVES: Numerous diseases and disorders are associated with mitochondrial DNA (mtDNA) mutations, among which m.1555A > G and m.1494C > T mutations in the 12 S ribosomal RNA gene contribute to aminoglycoside-induced and nonsyndromic hearing loss worldwide. METHODS: A total of 76,842 qualified non-invasive prenatal (NIPT) samples were subjected to mtDNA mutation and haplogroup analysis. RESULTS: We detected 181 m.1555A > G and m.1494C > T mutations, 151 of which were subsequently sequenced for full-length mitochondrial genome verification. The positive predictive values for the m.1555A > G and m.1494C > T mutations were 90.78% and 90.00%, respectively, a performance comparable to that attained with newborn hearing screening. Furthermore, mitochondrial haplogroup analysis revealed that the 12 S rRNA 1555A > G mutation was enriched in sub-haplotype D5[p = 0, OR = 4.6706(2.81-7.78)]. CONCLUSIONS: Our findings indicate that the non-invasive prenatal testing of cell-free DNA obtained from maternal plasma can successfully detect m.1555A > G and m.1494C > T mutations.