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Background: Combined first‐trimester screening (cFTS) for fetal anomalies involves maternal serum screening for biochemical markers and measurement of the nuchal translucency (NT) by ultrasound. Noninvasive prenatal screening (NIPS) analyses cell‐free DNA present in a maternal blood sample for presence of fetal chromosomal aneuploidies. Aims: To compare NIPS with cFTS as frontline screening in a public hospital in Australia. Materials and methods: Women were offered NIPS in addition to the usual cFTS routinely offered to all women at a public hospital in NSW, Australia. The cFTS sample was collected at ten weeks' gestation and the NIPS sample at 12 weeks' gestation at the ultrasound appointment. Results: In a low‐risk population of 997 women, frontline NIPS had a screen‐positive rate of 0.5% (5/997) vs 4.2% (42/997) with cFTS. cFTS correctly identified one trisomy 21 case and one trisomy 18 case; however, there were two trisomy 18 false negatives. Of five positive NIPS calls, four were correctly identified as trisomy 21 (one) and trisomy 18 (three); there were no NIPS false negatives. Overall, the false‐positive rate with NIPS was 0.1% vs 4.0% by cFTS. Conclusions: The lower screen‐positive rate with NIPS for common trisomies was a result of the significantly lower false‐positive rate with NIPS. Consequently, NIPS as first‐line screening, even if funded by the hospital, may provide cost savings. We believe NIPS should be used from ten weeks' gestation in conjunction with morphology ultrasound for routine first‐trimester prenatal management. [ABSTRACT FROM AUTHOR]

Noninvasive prenatal screening with cell-free DNA is now considered a first-line screening for common aneuploidies. Advancements in existing laboratory techniques now allow to interrogate the entirety of the fetal genome, and many commercial laboratories have expanded their screening panels to include screening for rare autosomal aneuploidies and copy number variants. Here, we review the currently available data on the performance of fetal cell-free DNA to detect rare autosomal aneuploidies and copy number variants that are associated with clinically significant microdeletion and microduplication syndromes and the current position of medical societies on routine screening for these syndromes. [ABSTRACT FROM AUTHOR]

Cell-free DNA (cfDNA) screening has high detection for the common fetal autosomal aneuploidies, but is not diagnostic. The positive predictive value should be utilized in counseling after a positive cell-free DNA screen, and diagnostic testing should be offered for confirmation. cfDNA screening does not report a result in ~3% of cases; nonreportable results indicate an increased risk for aneuploidy and some adverse perinatal outcomes. False-positive cfDNA screening occurs due to confined placental mosaicism, maternal copy number variants, mosaicism, and cancer. Pretest education and counseling should be provided with emphasis on the potential benefits, risks, and limitations before cfDNA screening. [ABSTRACT FROM AUTHOR]

Although nearly all noninvasive prenatal testing is currently based on analyzing circulating maternal cell-free DNA, the technical methods usedvary considerably. We review the different methods. Based on validation trials and clinical experience, there are mostly relatively small differences in screening performance for trisomies 21, 18, and 13 in singleton pregnancies. Recent reports show low no-call rates for all methods, diminishing its importance when choosing a laboratory. However, method can be an important consideration for twin pregnancies, screening for sex chromosome abnormalities, microdeletion syndromes, triploidy, molar pregnancies, rare autosomal trisomies, and segmental imbalances, and detecting maternal chromosome abnormalities. [ABSTRACT FROM AUTHOR]

Objectives: Unconjugated estriol (uE3) is used as a marker for fetal aneuploidy in maternal serum screening tests. The goal of this study was to examine the validity of a new immunoassay for uE3 that uses a monoclonal antibody (m-uE3) rather than the more commonly used polyclonal antibody (p-uE3). Setting: Assays were performed in the Special Chemistry laboratory at Women and Infants Hospital of Rhode Island. Methods: Residual fresh (n = 100) and frozen (n = 533) second trimester serum samples from routine clinical care were tested using p-uE3 and/or m-uE3 assays. Assay results were compared between methods using Bland–Altman plots. A median equation was developed for m-uE3 results. Down syndrome risks were compared between the two assays in a case–control sample set (21 cases each matched with five controls for the completed week of gestation, duration of freezer storage and race). Results: Log-transformed serum uE3 levels were highly correlated between the assays (r = 0.93, p < 0.001), with the m-uE3 assay levels yielding, on average, 23% higher (standard deviation of differences in log uE3 concentrations = 0.07) results. Assay and gestation-based median equations were calculated and used to convert m-uE3 concentrations to multiples of the median (MoM). The m-uE3 MoM values fit a log Gaussian distribution well with a log standard deviation of 0.11. Down syndrome risk results were not significantly different between assays. Conclusions: The m-uE3 assay, with results expressed in MoMs, is suitable for screening and as a monoclonal-based assay offers the advantage of a predictable and indefinite supply of antibody to perform the assay. [ABSTRACT FROM AUTHOR]

Non-invasive prenatal testing was first discovered in 1988; it was primarily thought to be able to detect common aneuploidies, such as Patau syndrome (T13), Edward Syndrome (T18), and Down syndrome (T21). It comprises a simple technique involving the analysis of cell-free foetal DNA (cffDNA) obtained through maternal serum, using advances in next-generation sequencing. NIPT has shown promise as a simple and low-risk screening test, leading various governments and private organizations worldwide to dedicate significant resources towards its integration into national healthcare initiatives as well as the formation of consortia and research studies aimed at standardizing its implementation. This article aims to review the reliability of NIPT while discussing the current challenges prevalent among different communities worldwide. [ABSTRACT FROM AUTHOR]

Trisomy 21 (Down syndrome) is the most common autosomal aneuploidy among newborns. About 90% result from meiotic nondisjunction during oogenesis, which occurs around conception, when also the most profound epigenetic modifications take place. Thus, maternal meiosis is an error prone process with an extreme sensitivity to endogenous factors, as exemplified by maternal age. This contrasts with the missing acceptance of causal exogenous factors. The proof of an environmental agent is a great challenge, both with respect to ascertainment bias, determination of time and dosage of exposure, as well as registration of the relevant individual health data affecting the birth prevalence. Based on a few exemplary epidemiological studies the feasibility of trisomy 21 monitoring is illustrated. In the nearer future the methodical premises will be clearly improved, both due to the establishment of electronic health registers and to the introduction of non-invasive prenatal tests. Down syndrome is a sentinel phenotype, presumably also with regard to other congenital anomalies. Thus, monitoring of trisomy 21 offers new chances for risk avoidance and preventive measures, but also for basic research concerning identification of relevant genomic variants involved in chromosomal nondisjunction. [ABSTRACT FROM AUTHOR]

Prenatal screening for aneuploidy has undergone immense changes over the past two decades. In 2013 cell‐free DNA‐based non‐invasive prenatal testing (NIPT) became a new self‐funded option primarily for Down syndrome screening, but also other aneuploidies and genetic conditions. The numbers of Medicare item claims for prenatal diagnostic procedures have halved since the introduction of NIPT, while billings for serum screening fell by 40% over the same period, on a background of steady births. Australia is now observing historically low rates of prenatal diagnostic testing. These data provide an informative snapshot of historic changes in prenatal screening and diagnosis, as our sector prepares for the impending impacts of other advances in genomics on maternity care. They also highlight the need to address equity and quality issues that arise when consumers must bear the full costs of improved genomic tests in the absence of Medicare funding. [ABSTRACT FROM AUTHOR]

Background: Fetal exposure to maternal anxiety is associated with low birth weight and maternal stress may be led to constriction of uterine arteries. This study compared the relation of anxiety and uterine artery doppler flow indices in pregnant women with the high and low-risk of Down syndrome. Materials and Methods: This prospective cohort study was conducted among pregnant women in the second trimester that were classified as having a high or low risk according to their prenatal aneuploidy screening outcome. The high risk group underwent amniocentesis. Anxiety was initially assessed using the Spielberger State-Anxiety Inventory (STAI) and uterine artery blood flow indices were evaluated 2 times for the both groups. For the high-risk group first: immediately before amniocentesis and second: after two weeks follow up, when receiving the karyotype results and for the low-risk group in the first admission and two weeks later. Results: Totally, 375 pregnant women participated in our study that sorted into 2 risk populations based on the aneuploidy screening test, low-risk=176 and high-risk women=199. The high-risk group for Down syndrome amniocentesis showed abnormal results in the 23 cases (23/199). The mean state (P=0.003) and trait (P=0.033) of the Anxiety Inventory scores were significantly different between the groups. Baseline uterine artery indices were no significant difference between the groups. Baseline Uterine artery indices in the high-risk group was significantly different with follow-up (in both positive-amniocentesis and negative amniocentesis sub-groups) indices. Also, there was a weak and significant correlation in the uterine resistance index and STAI scores (P=0.008, r=0.137) during the follow-up period. Conclusion: All pregnant women experienced high level anxiety, especially in the high-risk group that may reduce after confirmation of prenatal aneuploidy screening test and also affects the Doppler indices. For all pregnant women; Stress management and emotional support training is recommended before and during pregnancy. [ABSTRACT FROM AUTHOR]

Objective: We retrospectively analyzed our center’s experience with the prenatal diagnosis of isolated perimembranous ventricular septal defects that underwent primary surgical repair in infancy. Methods: We identified patients born in Southern Nevada, between October 2012 and October 2020, with prenatal care that underwent surgical closure of an isolated large perimembranous ventricular septal defect between 1 and 12 months of age. The description at surgery defined ventricular septal defect morphology. We included only those with situs solitus, levocardia without dextroposition, and without any other cardiovascular abnormality. We analyzed prenatal detection rates for each of the eight years. Results: We identified 81 patients. Of the 81, 35 (43%) had trisomy 21. We identified no other aneuploidies in those that underwent surgical repair; however, 1 had a 15q13.3 deletion syndrome, and 1 had a 22 q11.2 deletion syndrome. Of the 81, 27 (33%) overall were prenatally diagnosed. Increasing prenatal detection rates strongly correlated with time (R = 0.92, p = .002). Conclusions: Trisomy 21 is common in isolated perimembranous ventricular septal defects undergoing primary repair in infancy. Further, prenatal detection rates significantly improved over time, up to 65% detection in the current years. [ABSTRACT FROM AUTHOR]

Background: Non-invasive prenatal testing (NIPT) as a screening method for trisomy 21 and other chromosomal abnormalities has been adopted widely across the globe. However, while many clinical validation studies have been performed, less is known regarding the patient experience with NIPT. This study explored how individuals experience NIPT in a pre- and post-test setting, where NIPT is broadly available as a primary screening method with the option of reporting beyond common trisomies.Methods: Participants were recruited using social media with a strategy designed to select individuals who had the option to have NIPT as part of the TRIDENT-2 study (In the Netherlands, NIPT is only available within the TRIDENT studies executed by the NIPT consortium. This research was done independently from the NIPT consortium.) in the Netherlands. The study used online questionnaires and semi-structured interviews. Both were developed around a patient experience framework consisting of seven themes: information, patient as active participant, responsiveness of services, lived experience, continuity of care and relationships, communication, and support.Results: Overall, 4539 questionnaire responses were analyzed and 60% of the respondents had experienced NIPT. Of those, 1.7% received a high-risk result for trisomy or another chromosomal copy number variant (referred to as an "additional finding"). Overall, participants felt they had received sufficient information and had control over their decision regarding whether or not to choose NIPT. The vast majority of respondents who had NIPT were positive about their experience and would use it again. Those with results showing an increased probability for trisomy or additional findings were more likely to report negative feelings such as tension and anxiety, and less likely to feel that they had been sufficiently prepared for the implications of their results.Conclusions: The patient experience with first-tier NIPT in the Netherlands was largely positive. Areas for improvement included counseling on the implications of screening and the different possible outcomes of NIPT, including additional findings that may be uncovered by expanding NIPT beyond the common trisomies. The experiences reported in this study may be useful for other countries intending to implement NIPT. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the diagnostic value of the BACs-on-Beads (BoBs) assay for the rapid diagnosis of common aneuploidies and microdeletions.Methods: A total of 4961 pregnant women admitted to the Wuxi Maternity and Child Health Care Hospital Affiliated to Nanjing Medical University from January 2017 to March 2019 were enrolled. BoBs assay and conventional karyotyping were applied to detect amniotic fluid samples with various indications for prenatal diagnosis. Chromosomal microarray analysis (CMA) and maternal cell contamination (MCC) tests were used for further validation.Results: The overall abnormality detection rates (BoBs associated with karyotyping) were 4.25% (211/4961). The prenatal diagnosis success rate of karyotyping was 99.4% (4933/4961), compared to 100% (4961/4961) using the BoBs assays. The BoBs assay was similar to karyotyping for the detection of trisomy 21 (1.01%, 50/4961), trisomy 18 (0.40%, 20/4961), trisomy 13 (0.04%, 2/4961), and sex chromosomal aneuploidies (0.15%, 12/4961). The BoBs assay also identified sex chromosomal microduplications/microdeletions (1.73%, 86/4961), 22q11.2 microdeletions/microduplications (0.1%, 5/4961), and Cri du Chat syndrome (0.02%, 1/4961) which were missed by karyotyping. The sensitivity for the detection of numerical chromosomal abnormalities of the BoBs assay and karyotyping analysis was 100% (95/95, 95% CI: 1.0-1.0) and 98.9% (94/95, 95% CI: 0.969-1.010), respectively. The sensitivity of detecting structural chromosomal abnormalities in the BoBs assay was significantly higher than those of karyotyping (79.3%, 92/116, 95% CI: 0.718-0.868) versus 21.6% (25/116, 95% CI: 0.140-0.291) (p < .01).Conclusions: The BoBs assay is a reliable and rapid test for the detection of common aneuploidies and nine microdeletion syndromes with high sensitivity and accuracy in prenatal diagnosis. The assay can compensate for the limitations of karyotyping analysis. [ABSTRACT FROM AUTHOR]

Purpose: Noninvasive prenatal testing (NIPT) is a highly sensitive and specific method for detection of fetal chromosomal aneuploidies from maternal plasma. The objective of this study was to determine the performance of a new paired-end sequencing-based NIPT assay in 13,607 pregnancies from a single center in Germany.Methods: Samples from 13,607 pregnant women who previously underwent NIPT were analyzed using VeriSeq NIPT Solution v2 assay for presence of common fetal trisomies and monosomy X. Follow-up to determine clinical truth was carried out.Results: Of the 13,607 cases, 13,509 received a NIPT call resulting in a low study failure rate of 0.72%. There were 188 (1.4%) high-risk calls: 117 trisomy 21, 34 trisomy 18, 23 trisomy 13, one trisomy 21 + 13, and 13 monosomy X. High sensitivities and specificities of ≥ 98.89% were reported for all four aneuploidy conditions. Of the high-risk cases, clinical follow-up data were available for 77.1% (145/188). Clinical follow-up of high-risk calls revealed an overall positive predictive value of 84.8% (potential range 65.4-88.3%). NIPT results were provided for samples across a range of fetal fractions, down to 2% fetal fraction.Conclusion: The VeriSeq NIPT Solution v2 assay detected fetal chromosomal aneuploidies across a range of fetal fractions with high sensitivities and specificities observed based on known clinical outcomes, a high overall PPV, and a low failure rate. [ABSTRACT FROM AUTHOR]

Background: This paper describes the clinical practice and performance of cell-free DNA sequencing-based non-invasive prenatal testing (NIPT) as a screening method for fetal trisomy 21, 18, and 13 (T21, T18, and T13) and sex chromosome aneuploidies (SCA) in a general Italian pregnancy population. Methods: The AMES-accredited laboratory offers NIPT in maternal blood as a screening test for fetal T21, T18, T13 and SCA. Samples were sequenced on a NextSeq 550 (Illumina) using the VeriSeq NIPT Solution v1 assay. Results: A retrospective analysis was performed on 36,456 consecutive maternal blood samples, including 35,650 singleton pregnancies, 800 twin pregnancies, and 6 triplet pregnancies. Samples were tested between April 2017 and September 2019. The cohort included 46% elevated-risk and 54% low-risk patients. A result indicative of a classic trisomy was found in 356 (1%) of singleton or twin samples: 254 T21, 69 T18, and 33 T13. In addition, 145 results (0.4%) were indicative of a SCA. Of the combined 501 screen-positive cases, 484 had confirmatory diagnostic testing. NIPT results were confirmed in 99.2% (247/249) of T21 cases, 91.2% (62/68) of T18 cases, 84.4% (27/32) of T13 cases, and 86.7% (117/135) of SCA cases. In the 35,955 cases reported as unaffected by a classic trisomy or SCA, no false negative cases were reported. Assuming that false negative results would be reported, the sensitivity of NIPT was 100.00% for T21 (95% Cl 98.47–100.0), T18 (95% Cl 94.17–100.0), and T13 (95% Cl 87.54–100.0). The specificities were 99.99% (95% Cl 99.98–100.0), 99.98% (95% Cl 99.96–100.0), 99.99% (95% Cl 99.97–100.0), and 99.95% (95% Cl 99.92–99.97) for T21, T18, T13, and SCA, respectively. Conclusion: This retrospective analysis of a large cohort of consecutive patients who had whole-genome sequencing-based NIPT for classic trisomies and SCA shows excellent detection rates and low false positive rates. [ABSTRACT FROM AUTHOR]

Background: This paper describes the clinical practice and performance of cell-free DNA sequencing-based non-invasive prenatal testing (NIPT) as a screening method for fetal trisomy 21, 18, and 13 (T21, T18, and T13) and sex chromosome aneuploidies (SCA) in a general Italian pregnancy population. Methods: The AMES-accredited laboratory offers NIPT in maternal blood as a screening test for fetal T21, T18, T13 and SCA. Samples were sequenced on a NextSeq 550 (Illumina) using the VeriSeq NIPT Solution v1 assay. Results: A retrospective analysis was performed on 36,456 consecutive maternal blood samples, including 35,650 singleton pregnancies, 800 twin pregnancies, and 6 triplet pregnancies. Samples were tested between April 2017 and September 2019. The cohort included 46% elevated-risk and 54% low-risk patients. A result indicative of a classic trisomy was found in 356 (1%) of singleton or twin samples: 254 T21, 69 T18, and 33 T13. In addition, 145 results (0.4%) were indicative of a SCA. Of the combined 501 screen-positive cases, 484 had confirmatory diagnostic testing. NIPT results were confirmed in 99.2% (247/249) of T21 cases, 91.2% (62/68) of T18 cases, 84.4% (27/32) of T13 cases, and 86.7% (117/135) of SCA cases. In the 35,955 cases reported as unaffected by a classic trisomy or SCA, no false negative cases were reported. Assuming that false negative results would be reported, the sensitivity of NIPT was 100.00% for T21 (95% Cl 98.47–100.0), T18 (95% Cl 94.17–100.0), and T13 (95% Cl 87.54–100.0). The specificities were 99.99% (95% Cl 99.98–100.0), 99.98% (95% Cl 99.96–100.0), 99.99% (95% Cl 99.97–100.0), and 99.95% (95% Cl 99.92–99.97) for T21, T18, T13, and SCA, respectively. Conclusion: This retrospective analysis of a large cohort of consecutive patients who had whole-genome sequencing-based NIPT for classic trisomies and SCA shows excellent detection rates and low false positive rates. [ABSTRACT FROM AUTHOR]

Introduction: Austere clinical settings, including remote military installations, face unique challenges in screening pregnant women for aneuploidy. The objective of this study was to compare the direct and indirect prenatal costs of traditional 2-part serum-based screening to cell-free DNA (cfDNA) for detection of trisomies 18 and 21 for a military treatment facility with limited in-house perinatal resources.Materials and Methods: We identified Naval Hospital Guantanamo Bay as a surrogate for an austere clinical environment. A prenatal cost of care analysis incorporating direct and indirect expenses was performed to compare the 2 aneuploidy screening strategies for a theoretical cohort of 100 patients for detection of trisomies 18 and 21. The baseline aneuploidy uptake rate was determined using a historical cohort. Test performance characteristics were obtained from the contracting laboratory. Aneuploidy rates and costs were calculated using previously published data.Results: Assuming a baseline screen uptake rate of 87%, initial screening using the traditional approach would directly cost $8,285.01 versus $44,140.32 with cfDNA. Considering indirect costs such as travel, consultative services, evaluation and follow-up testing of an abnormal screen result, and lost productivity, the cost difference narrows to $14,458.25 over a 5- to 6-year period. Cost equivalence is achieved when cfDNA is priced at $341.17 per test.Conclusion: Cell-free DNA as an initial screening strategy offers enhanced detection rates for trisomies 18 and 21 but remains more costly than traditional screening when incorporating direct and indirect expenses. In a low volume setting with limited resources, the added cost may be justified given the implications of unrecognized aneuploidy. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this survey is to evaluate the knowledge of Chinese pregnant women about fetal chromosomal aneuploidy and microdeletion and microduplication syndromes, and Non-invasive prenatal testing (NIPT).Study Design: Written questionnaires were distributed to pregnant women who visited the fetal medicine clinic of the third affiliated hospital of Guangzhou medical university. A total of 330 questionnaires were given. Twenty-two questionnaires with incomplete information were excluded from further analysis. The remaining 308 cases were incorporated into the final analysis. Data were analyzed using IBM SPSS Statistics 26. Comparisons between categorical variables were tested by the use of crosstabs and χ 2 test.Results: Among pregnant women, the recognition of Down syndrome was the highest (93.5 %), followed by maternal serum screening (74.0 %) and NIPT (69.2 %) for chromosomal aneuploidy. The awareness rates of chromosomal microdeletions and microduplications (18.2 %) and monogenic disorders (13.3 %) were the lowest. There were no significant differences in age, education, and conception way between pregnant women (P > 0.05). When asked the opinion on increasing the testing range of NIPT, more than 50 % of pregnant women chose to follow the provider's advice.Conclusion: More than half of pregnant women lacked knowledge of screening methods for fetal chromosomal abnormalities. Less than 20 % of pregnant women knew microdeletion microduplication syndromes. To enhance the understanding of chromosomal abnormalities can ensure that women can actively choose tests rather than passively agreeing to their provider's recommendations so as to avoid missing the optimal prenatal screening time. [ABSTRACT FROM AUTHOR]

Clinical performance of the Momguard non-invasive prenatal test (NIPT) was evaluated in a cohort of Korean pregnant women. The foetal trisomies 21, 18 and 13 (T21, T18 and T13) were screened by low-coverage massive parallel sequencing in the maternal blood. Among the 1011 confirmed samples, 32 cases (3.2%) had positive NIPT results. Of these positive cases, 20 cases of T21, all cases of T18 and two cases of T13 had concordant karyotype findings. Only one case out of the remaining 979 negative NIPT samples showed a false negative result. The overall sensitivity and specificity of Momguard to detect the three chromosomal aneuploidies were 96.8% and 99.8%, respectively. Momguard is a clinically useful tool for the detection of T21, T18 and T13 in singleton pregnancy. However, as other NIPT tests, it carries the risk of false positive and false negative results. Hence, the genetic counsellors should provide these limitations to the examinees.Impact StatementWhat is already known on this subject? The NIPT approach using massive parallel sequencing (MPS) showed high sensitivity and specificity in various clinical studies. These results are based on analysis systems using their own bioinformatics algorithms.What the results of this study add? When this NIPT technology was introduced in Korea, the first biological specimens collected in Korea were transported overseas for processing in overseas laboratories and analysed by other country's analysis methods. We needed our own NIPT algorithm and developed Momguard NIPT for the first time in Korea. This study attempted to evaluate this Momguard NIPT protocol prospectively in a large number of samples obtained from three Korean hospitals.What the implications are of these findings for clinical practice and/or further research? The overall sensitivity and specificity to identify T13, T18 and T21 were 96.8% and 99.8%, respectively. These accuracy values were comparable to that of other studies. From this study, we found that Momguard is a clinically useful tool for the detection of three chromosomal aneuploidies. However, as other NIPT tests, it carries the risk of false positive and false negative results. Hence, the genetic counsellors should provide these limitations to the examinees. [ABSTRACT FROM AUTHOR]

Background: The goal of this study was to determine whether Levey-Jennings charts, which are widely used in clinical laboratories, can be used to create standardized internal quality controls (IQCs) for prenatal molecular diagnosis. Methods: Aneuploid amniocyte lines with trisomy 13, 21, and 18, and 47,XXY were established by transfection with SV40LTag-pcDNA3.1(−)and combined at different ratios to generate aneuploidy chimeric quality-control cell mixtures A to H. These quality-control cells were then used to calculate the X ¯ , X ¯ ±1 standard deviation (SD), X ¯ ±2 SD, and X ¯ ±3 SD values to develop standardized IQCs for methods used for the prenatal diagnosis of aneuploidies such as FISH. Results: Methods for constructing aneuploid amniocyte lines were developed and a set of quality-control cells (A-H) were prepared. The X ¯ ±1 SD, X ¯ ±2 SD, and X ¯ ±3 SD values of these quality-control cells for trisomy 13 and 21 were 10.2 ± 1.7, 10.2 ± 3.4, and 10.2 ± 5.1, and 90.3 ± 2.3, 90.3 ± 4.6, and 90.3 ± 6.9, respectively. Based on the values and Levey-Jennings charts, a set of standardized IQCs for prenatal diagnosis such as FISH were established. Conclusions: This method resolves the problems of a shortage of quality-control materials and a lack of quality-control charts in prenatal molecular diagnosis such as NIPT, NGS, aCGH/SNP, PCR, and FISH. Levey-Jennings chart-based IQCs for prenatal diagnosis such as FISH can be used to easily monitor whether IQC results are within acceptable limits, and then infer whether the diagnostic results for clinical samples are reliable. We expect that this standardized IQC will be useful for a wide range of molecular diagnostic laboratories. [ABSTRACT FROM AUTHOR]

Objective: To assess whether the cisterna magna (CM) width measured in first-trimester fetuses is a useful marker for aneuploidy detection.Methods: This was a prospective study in 2 different cohorts in a tertiary referral center. The first cohort comprised 913 fetuses from the general pregnancy population during the period 2012-2016 and was used to construct the CM reference ranges applying the λ-μ-σ (LMS) method. The second cohort included 714 high-risk fetuses undergoing chorionic villus sampling during the period 2012-2016. Mean detection rates using the 95th percentile for CM width observed in chromosomal anomaly groups were compared with those obtained in chromosomally normal fetuses.Results: The 50th percentile for CM ranged from 1.66 to 2.75 mm when crown-rump length (CRL) increased from 45 to 84 mm. Among high-risk fetuses, the following chromosomal anomalies were diagnosed in 125 (17%) fetuses: trisomy 21 (n = 63), trisomy 18 or 13 (n = 21), monosomy X (n = 9), submicroscopic anomalies (n = 11), and other anomalies (n = 22). The mean CM width for euploid fetuses was 2.4 mm (1.13 multiples of the median, MoM). While CM width was significantly increased in trisomy 21 (mean 2.7 mm; 1.23 MoM; p > 0.05), no differences were found in the other anomaly groups. Among the 63 fetuses with trisomy 21, a CM width above the 99th percentile was observed in 23 fetuses (37%).Conclusions: The new reference range for CM width at 11-13 weeks of gestation did not differ from previous studies. In first-trimester fetuses with trisomy 21, CM width appears to be increased, although its value as an ultrasound marker is limited, because of its detection rate of 37%. [ABSTRACT FROM AUTHOR]

Prenatal diagnosis of Down syndrome (DS) is based on calculated risk involving maternal age, biochemical and ultrasonographic markers, and, more recently, cell-free DNA (cfDNA). The present study was designed to identify Down Syndrome biomarkers in maternal serum. We quantified the changes in maternal serum protein levels between 10 non-pregnant women, 10 pregnant women with healthy fetuses, and 10 pregnant women with DS fetuses using isobaric tags for relative and absolute quantification (iTRAQ). We subsequently conducted a Gene Ontology (GO) analysis. A total of 470 proteins were identified, 11 of which had significantly different serum levels between the DS fetus group and Healthy fetuses group. Our data shows the identified proteins may be relevant to DS and constitute potential DS biomarkers. [ABSTRACT FROM AUTHOR]

Objective: To assess the frequency of atypical chromosomal and submicroscopic anomalies, as well as fetal structural abnormalities, observed on first-trimester ultrasound scan in fetuses with nuchal translucency (NT) thickness > 99th centile, in order to evaluate the suitability of using standard cell-free DNA (cfDNA) testing as the sole screening test in these pregnancies.Methods: This was a retrospective cohort study of 226 fetuses with NT > 99th centile at 11-14 weeks' gestation, between January 2013 and December 2017, in a clinical setting in which greater than 95% of pregnant women receive first-trimester combined screening. All patients underwent genetic testing by means of quantitative fluorescence polymerase chain reaction and chromosomal microarray analysis, mainly in chorionic villus samples. We assessed the theoretical yield of two cfDNA testing models, targeted cfDNA (chromosomes 21, 18 and 13) and extended cfDNA (chromosomes 21, 18, 13 and sex chromosomes), and compared it with that of cytogenetic testing and ultrasound assessment in the first and second or third trimesters.Results: In the 226 fetuses analyzed, cytogenetic testing revealed 84 (37%) anomalies, including 68 typical aneuploidies (involving chromosomes 13, 18 or 21), six sex chromosome aneuploidies (four cases of monosomy X and two of trisomy X), three clinically relevant atypical chromosomal anomalies (one trisomy 22, one trisomy 21 mosaicism and one unbalanced translocation), five submicroscopic pathogenic variants and two cases with Noonan syndrome. Targeted and extended cfDNA testing would miss at least 12% (10/84) and 19% (16/84), respectively, of genetic anomalies, accounting for 4.4% and 7.1% of the fetuses with an increased NT, respectively. Finally, of the 142 fetuses with no identified genetic anomaly, a major fetal malformation was observed in 15 (10.6%) fetuses at the early anomaly scan, and in 19 (13.4%) in the second or third trimester.Conclusions: cfDNA does not appear to be the appropriate genetic test in fetuses with NT > 99th centile, given that it would miss 12-19% of genetic anomalies in this group. Additionally, first-trimester ultrasound will identify a major structural abnormality in 11% of the fetuses with NT > 99th centile and no genetic anomaly. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Background: The quantitative fluorescent polymerase chain reaction (QF-PCR) has proven to be a reliable method for detection of common fetal chromosomal aneuploidies. However, there are some technical shortcomings, such as uncertainty of aneuploidy determination when the short tandem repeats (STR) height ratio is unusual due to a large size difference between alleles or failure due to the presence of maternal cell contamination (MCC). The aim of our study is to facilitate the implementation of the QF-PCR as a rapid diagnostic test for common fetal aneuploidies. Methods: Here, we describe an in-house one-tube multiplex QF-PCR method including 20 PCR markers (15 STR markers and 5 fixed size) for rapid prenatal diagnosis of chromosome 13, 18, 21, X and Y aneuploidies. In order to improve the aneuploidy classification of a given diallelic STR marker, we have employed a multilevel logistic regression analysis using "height-ratio" and "allele-size-difference" as fixed effects and "marker" as a random effect. We employed two regression models, one for the 2:1 height ratio (n = 48 genotypes) and another for the 1:2 height ratio (n = 41 genotypes) of the trisomic diallelic markers while using the same 9015 genotypes with normal 1:1 height ratio in both models. Furthermore, we have described a simple procedure for the treatment of the MCC, prior DNA isolation and QF-PCR analysis. Results: For both models, we have achieved 100% specificity for the marker aneuploidy classification as compared to 98.60% (2:1 ratio) and 98.04% (1:2 ratio) specificity when using only the height ratio for classification. Treatment of the MCC enables a successful diagnosis rate of 76% among truly contaminated amniotic fluids. Conclusions: Adjustment for the allele size difference and marker type improves the STR aneuploidy classification, which, complemented with appropriate treatment of contaminated amniotic fluids, eliminates sample re-testing and reinforces the robustness of the QF-PCR method for prenatal testing. [ABSTRACT FROM AUTHOR]

Since introducing cell-free DNA screening, Sequenom Laboratories has analyzed over 1 million clinical samples. More than 30,000 of these samples were from multifetal gestations (including twins, triplets and higher-order multiples). The clinical laboratory experience with the first 30,000 multifetal samples will be discussed. Maternal plasma samples from multifetal gestations were subjected to DNA extraction and library preparation followed by massively parallel sequencing. Sequencing data were analyzed to identify autosomal trisomies and other subchromosomal events. Fetal fraction requirements were adjusted in proportion to fetal number. Outcome data, when voluntarily received from the ordering provider, were collected from internal case notes. Feedback was received in 50 cases. The positivity rate in multifetal samples for trisomy 21 was 1.50%, 0.47% for trisomy 18, and 0.21% for trisomy 13. Average total sample fetal fraction was 12.2% at a mean gestational age of 13 weeks 6 days. Total non-reportable rate was 5.95%. Estimated performance based on ad hoc clinical feedback demonstrates that possible maximum sensitivity and specificity meet or exceed the original performance from clinical validation studies. Cell-free DNA (cfDNA) screening provides certain advantages over that of conventional screening in multifetal gestations and is available in higher-order multiples. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the clinical and economic impact of adopting noninvasive prenatal testing (NIPT) using circulating cell-free DNA as a first-line screening method for trisomy 21, 18, and 13 in the general pregnancy population.Methods: A decision-analytical model was developed to assess the impact of adopting NIPT as a primary screening test compared to conventional screening methods. The model takes the Belgium perspective and includes only the direct medical cost of screening, diagnosis, and procedure-related complications. NIPT costs are EUR 260. Clinical outcomes and the cost per trisomy detected were assessed. Sensitivity analysis measured the impact of NIPT false-positive rate (FPR) on modelled results.Results: The cost per trisomy detected was EUR 63,016 for conventional screening versus EUR 66,633 for NIPT, with a difference of EUR 3,617. NIPT reduced unnecessary invasive tests by 94.8%, decreased procedure-related miscarriages by 90.8%, and increased trisomies detected by 29.1%. Increasing the FPR of NIPT (from < 0.01 to 1.0%) increased the average number of invasive procedures required to diagnose a trisomy from 2.2 to 4.5, respectively.Conclusion: NIPT first-line screening at a reasonable cost is cost-effective and provides better clinical outcomes. However, modelled results are dependent on the adoption of an NIPT with a low FPR. [ABSTRACT FROM AUTHOR]

Objective: To determine the association between second-trimester serum Down syndrome screening (alpha-fetoprotein [AFP] free beta-human chorionic gonadotropin [b-hCG] unconjugated estriol [uE3]) and preterm birth and to create predictive models for preterm birth.Methods: Secondary analysis on a prospective database of pregnancies undergoing second-trimester screen with complete follow-up. The multiples of medians (MoM) of the biomarkers were compared between the group of term, preterm (< 37 weeks), early preterm (< 34 weeks), and very early preterm (< 32 weeks) delivery. Predictive models were developed based on adjusted MoMs and logistic regression and diagnostic performances in predicting preterm birth were determined.Results: Of 20,780 pregnancies, 1,554 (7.5), 363 (1.7), and 158 (0.8%) had preterm, early preterm, and very early preterm birth respectively. High levels of AFP and b-hCG but low levels of uE3 were significantly associated with higher rates of preterm, early preterm and very early preterm delivery. The predictive models had diagnostic performance in predicting preterm birth with the areas under the ROC curve of 0.688, 0.534, 0.599, and 0.718 for AFP, b-hCG, uE3, and combined biomarkers respectively.Conclusion: The second trimester Down syndrome screening could also be used as a tool of risk identification of preterm birth in the same test, without extra-effort and extra-cost. [ABSTRACT FROM AUTHOR]

Objective  The objective of this study was to evaluate risk factor prevalence in pregnancies with fetal Down syndrome, in an effort to characterize efficacy of population-based screening. Study Design  Retrospective review of singleton pregnancies with delivery of live born or stillborn infant with Down syndrome from 2009 through 2015. Risk factor categories included maternal age ≥35 years, abnormal serum screening, identification of ≥1 ultrasound marker at 16 to 22 weeks (nuchal thickness ≥6 mm, echogenic intracardiac focus, echogenic bowel, renal pelvis dilatation, femur length 50% of fetuses in women <35 years and in >75% of those 35 years and older. Conclusion  In a population-based cohort, sensitivity of second-trimester Down syndrome screening was 93%, with multiple risk factors present in nearly three-fourths of cases. [ABSTRACT FROM AUTHOR]

Objectives Non-invasive prenatal aneuploidy testing (NIPT) by next-generation sequencing of circulating cell-free DNA in maternal plasma relies on chromosomal ratio (chr ratio ) measurements to detect aneuploid values that depart from euploid ratios. Diagnostic performances are known to depend on the fraction of fetal DNA ( FF ) present in maternal plasma, although how this translates into specific quantitative changes in specificity/positive predictive values and which other variables might also be important is not well understood. Design & methods To explore this issue, theoretical relationships between FF and various measures of diagnostic performances were assessed for a range of parameter values. Empirical data from three NIPT assays were then used to validate theoretical calculations. Results For a given positivity threshold, dramatic changes in specificity and positive predictive values (PPV) as a function of both FF and the coefficient of variation (CV) of the chr ratio measurement were observed. Theoretically predicted and observed chr ratio z-scores agreed closely, confirming the determinant impact of small changes in both FF and chr ratio CV. Conclusions Evaluation of NIPT assay performances therefore requires knowledge of the FF distribution in the population in which the test is intended to be used and, in particular, of the precise value of the assay chr ratio CV for each chromosome or genomic region of interest. Laboratories offering NIPT testing should carefully measure these parameters to ensure test reliability and clinical usefulness in interpreting individual patients' results. [ABSTRACT FROM AUTHOR]

Cell‐free DNA screening has quickly become established in Australia as an accurate – albeit costly – prenatal screening test for trisomy 21, 18 and 13. It is also commonly used for the detection of sex chromosome abnormalities. The increasing number of prenatal screening pathways available to women has increased the complexity of pretest counselling. Concurrent advances in diagnostic testing with the widespread use of chromosomal microarrays create further challenges for the continuing education of clinicians and health consumers. This article aims to answer common clinical questions in this rapidly evolving field and complements the recently updated Royal Australian and New Zealand College of Obstetricians and Gynaecologists Statement on Prenatal Screening for Fetal Chromosome and Genetic Conditions. [ABSTRACT FROM AUTHOR]

Objectives We have established an open source platform for non-invasive prenatal testing (NIPT) based on massively parallel whole-genome sequencing in a public setting. The objective of this study was to investigate factors of importance for correct interpretation of NIPT results to ensure a high sensitivity and specificity. Study design This investigation is a retrospective case-control study performed in a public NIPT center. The study included 108 aneuploid cases and 165 euploid controls. MPS was performed on circulating cell-free DNA in maternal blood. The pipeline included automated library preparation and sequencing on a HiSeq1500 (Illumina). The software programmes WISECONDOR and SeqFF were used for data analysis of aneuploidy status and fetal fraction of cell-free DNA, respectively. Lower limit of fetal fraction for aneuploidy testing was 0.02. Results We identified four false negative aneuploidy cases of which two were explained by a vanishing twin. The number of no-call cases due to low fetal fraction was 8 out of 273 (2.9%). The sensitivity and specificity, when no-calls and vanished twins were excluded, were 100% and 99.5% for T21, 91% and 99.2% for T18, and 100% and 99.6% for T13. By multiple regression analysis we found a significant association between fetal fraction and gestational age, maternal BMI and ART treatment. Conclusion With a non-commercial open source NIPT set-up having the same high test-performance as reported by large private laboratories, we show that fetal fraction, a vanishing twin, BMI, gestational age and ART treatment are important factors in the interpretation of NIPT results. [ABSTRACT FROM AUTHOR]

DNA methylation is the most characterized epigenetic process exhibiting stochastic variation across different tissues and individuals. In non-invasive prenatal testing (NIPT) fetal specific methylated regions can potentially be used as biomarkers for the accurate detection of fetal aneuploidies. The aim of this study was the investigation of inter-individual methylation variability of previously reported fetal-specific markers and their implementation towards the development of a novel NIPT assay for the detection of trisomies 13, 18, and 21. Methylated DNA Immunoprecipitation (MeDIP) combined with in-solution targeted enrichment followed by NGS was performed in 29 CVS and 27 female plasma samples to assess inter-individual methylation variability of 331 fetal-specific differentially methylated regions (DMRs). The same approach was implemented for the NIPT of trisomies 13, 18 and 21 using spiked-in (n = 6) and pregnancy samples (n = 44), including one trisomy 13, one trisomy 18 and four trisomy 21. Despite the variability of DMRs, CVS samples showed statistically significant hypermethylation (p<2e-16) compared to plasma samples. Importantly, our assay correctly classified all euploid and aneuploid cases without any false positive results (n = 44). This work provides the starting point for the development of a NIPT assay based on a robust set of fetal specific biomarkers for the detection of fetal aneuploidies. Furthermore, the assay’s targeted nature significantly reduces the analysis cost per sample while providing high read depth at regions of interest increasing significantly its accuracy. [ABSTRACT FROM AUTHOR]

Introduction: Prenatal diagnosis of Down syndrome (DS) is based on the calculated risk of maternal age, biochemical and ultrasonographic markers and recently by cfDNA. Differences in proteomic profiles may give an opportunity to find new biomarkers.Objective: Characterize proteome of serum of mothers carrying DS fetus.Material and Methods: Blood serum samples of three groups of women were obtained, (a) 10 non-pregnant, (b) 10 pregnant with healthy fetus by ultrasound evaluation, (c) nine pregnant with DS fetus. Sample preparation was as follows: Albumin/IgG depletion, desalting, and trypsin digestion; the process was performed in nanoUPLC MS/MS. Data analysis was made with Mass Lynx 4.1 and ProteinLynx Global Server 3.0, peptide and protein recognition by MASCOT algorithm and UNIPROT-Swissprot database.Results: Each group showed different protein profiles. Some proteins were shared between groups. Only sera from pregnant women showed proteins related to immune and clot pathways. Mothers with DS fetus had 42 specific proteins.Conclusions: We found a different serum protein profile in mothers carrying DS fetuses that do not reflect expression of genes in the extra chromosome. Further studies will be necessary to establish the role of these proteins in aneuploid fetus and analyze their possible use as potential biomarkers. [ABSTRACT FROM AUTHOR]

Background: Early diagnosis of prenatal illnesses and timely treatment of congenital anomalies has been the mainstay of the health system. In this study, our aim is to provide Roc curve multivariate modeling in detection of fetal abnormalities using associated markers in screening Down syndrome in the first and second periods of pregnancy. Materials and Methods: This is a descriptive-analytical study that uses information from two sets of data. In the first set, 152 individuals, who had the results of the first- trimester and second screening tests at risk and in the second group, 75 individuals with normal results. The studied variables included the serum markers in the first- trimester and the second- trimester screening, auxiliary variables (includes demographic information). Statistical analysis was performed by using ROC regression, incremental value analysis and Stata 12 software. Results: In evaluating the value of each diagnostic test in the presence of auxiliary variables using logistic regression and rock curves, the results generally showed that in screening the first- trimester of PAPP-A and in the screening the second-trimester,Inhibin-A can be used alone as a diagnostic test. Conclusion: Best diagnostic test in the first- trimester, respectively, PPAP-A, NT, FREE B-HCG and in the second- trimester of screening, respectively, Inhibin-A, HGG, UE3 and AFP were based on the area under the ROC curve. In addition, the most significant effect of the predictor variable on the outcome of the diagnostic test was family history. [ABSTRACT FROM AUTHOR]

Non-invasive prenatal testing (NIPT), based on analysis of cell-free foetal DNA, is rapidly becoming a preferred method to screen for chromosomal aneuploidy with the technology now available in over 90 countries. This review provides an up-to-date discussion of the key clinical, social and ethical implications associated with this revolutionary technology. Stakeholders are positive about a test that is highly accurate, safe, can be perfomed early in pregnancy, identifies affected pregnancies that might otherwise have been missed and reduces the need for invasive testing. Nevertheless, professional societies currently recommend it as an advanced screening test due to the low false positive rate (FPR). Despite the practical and psychological benefits, a number of concerns have been raised which warrant attention. These include the potential for routinisation of testing and subsequent impact on informed decision-making, an "easy" blood test inadvertently contributing to women feeling pressured to take the test, fears NIPT will lead to less tolerance and support for those living with Down syndrome and the heightened expectation of having "perfect babies". These issues can be addressed to some extent through clinician education, patient information and establishing national and international consensus in the development of comprehensive and regularly updated guidelines. As the number of conditions we are able to test for non-invasively expands it will be increasingly important to ensure pre-test counselling can be delivered effectively supported by knowledgeable healthcare professionals. [ABSTRACT FROM AUTHOR]

From January 1st 2013 to August 31st 2016, 24408 pregnant women received the first trimester Combined test and contingently offered second trimester maternal serum screening to identify those women who would most benefit from invasive prenatal diagnosis (IPD). The screening was based on first trimester cut-offs of ≥1:30 (IPD indicated), 1:31 to 1:899 (second trimester screening indicated) and ≤1:900 (no further action), and a second trimester cut-off of ≥1:250. From January 2014, analysis of fetal cells from peripheral maternal blood was also offered to women with positive screening results. For fetal Down syndrome, the overall detection rate was 96.8% for a false-positive rate of 2.8% resulting in an odds of being affected given a positive result (OAPR) of 1:11, equivalent to a positive predictive value (PPV) of 8.1%. Additional chromosome abnormalities were also identified resulting in an OAPR for any chromosome abnormality of 1:6.6 (PPV 11.9%). For a sub-set of cases with positive contingent test results, FISH analysis of circulating fetal cells in maternal circulation identified 7 abnormal and 39 as normal cases with 100% specificity and 100% sensitivity. We conclude that contingent screening using conventional Combined and second trimester screening tests is effective but can potentially be considerably enhanced through the addition of fetal cell analysis. [ABSTRACT FROM AUTHOR]

Background: Since the introduction of non-invasive prenatal testing (NIPT) in 2011, mainly by commercial companies, a growing demand for NIPT from the public and healthcare professionals has been putting pressure on the healthcare systems of various countries. This study identifies the challenges of establishing a responsible implementation of NIPT for aneuploidy in prenatal healthcare, by looking at the Netherlands.Methods: A mixed methods approach involving 13 stakeholder interviews, document analysis and (participatory) observations of the Dutch NIPT Consortium meetings were used. The Diffusion of Innovation Theory and a Network of Actors model were used to interpret the findings.Results: Implementation of NIPT was facilitated by several factors. The set-up of a national NIPT Consortium enabled discussion and collaboration between stakeholders. Moreover, it led to the plan to offer NIPT through a nationwide research setting (TRIDENT studies), which created a learning phase for careful implementation. The Dutch legal context was perceived as a delaying factor, but eventually gave room for the parties involved to organise themselves and their practices.Conclusions: This study shows that implementing advanced technologies with profound effects on prenatal care benefit from a learning phase that allows time to carefully evaluate the technical performance and women's experiences and to enable public debate. Such a coordinated learning phase, involving all stakeholders, will stimulate the process of responsible and sustainable implementation. [ABSTRACT FROM AUTHOR]

Background: While non-invasive prenatal testing (NIPT) for fetal aneuploidy is commercially available in many countries, little is known about how obstetric professionals in non-Western populations perceive the clinical usefulness of NIPT in comparison with existing first-trimester combined screening (FTS) for Down syndrome (DS) or invasive prenatal diagnosis (IPD), or perceptions of their ethical concerns arising from the use of NIPT.Methods: A cross-sectional survey among 327 obstetric professionals (237 midwives, 90 obstetricians) in Hong Kong.Results: Compared to FTS, NIPT was believed to: provide more psychological benefits and enable earlier consideration of termination of pregnancy. Compared to IPD, NIPT was believed to: provide less psychological stress for high-risk women and more psychological assurance for low-risk women, and offer an advantage to detect chromosomal abnormalities earlier. Significant differences in perceived clinical usefulness were found by profession and healthcare sector: (1) obstetricians reported more certain views towards the usefulness of NIPT than midwives and (2) professionals in the public sector perceived less usefulness of NIPT than the private sector. Beliefs about earlier detection of DS using NIPT were associated with ethical concerns about increasing abortion. Participants believing that NIPT provided psychological assurance among low-risk women were less likely to be concerned about ethical issues relating to informed decision-making and pre-test consultation for NIPT.Conclusions: Our findings suggest the need for political debate initially on how to ensure pregnant women accessing public services are informed about commercially available more advanced technology, but also on the potential implementation of NIPT within public services to improve access and equity to DS screening services. [ABSTRACT FROM AUTHOR]

Objectives: An association between isolated, increased nuchal translucency thickness (NT) and pathogenic findings on chromosomal microarray analysis (CMA) has been reported. A recent meta-analysis reported that most studies use a NT cut-off value of 3.5 mm. However, considering NT distribution and the commonly accepted 5% false-positive rate in maternal serum screening, NT cut-off levels should be reconsidered. The aim of this study was to assess different NT cut-off levels as indication for CMA and to determine whether CMA should be recommended for mildly increased NT of 3.0-3.4 mm.Methods: This was a retrospective, multicenter study of singleton pregnancies with CMA results and either normal NT and no other finding or with increased NT as the only medical indication for CMA at the time of an invasive procedure (increased NT was considered an isolated finding in cases of advanced maternal age). Women with normal fetal NT who underwent CMA did so at their own request. A single laboratory performed all genetic analyses. Comparative genomic hybridization microarray analysis or single nucleotide polymorphism array technology was used for CMA. If combined first-trimester screening (NT and biochemistry) indicated increased risk for common aneuploidies, the case was excluded. NT was used to divide cases into three groups (≤ 2.9 mm, 3.0-3.4 mm and ≥ 3.5 mm) and their CMA results were compared.Results: CMA results were recorded in 1588 pregnancies, among which 770 fetuses had either normal NT with no other finding or isolated increased NT. Of these, 462 had NT ≤ 2.9 mm, 170 had NT of 3.0-3.4 mm and 138 had NT ≥ 3.5 mm. Pathogenic copy number variants were found in 1.7%, 6.5% and 13.8% of cases, respectively.Conclusion: Our results suggest that CMA should be recommended when fetuses have isolated, mildly increased NT (3.0-3.4 mm). Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd. [ABSTRACT FROM AUTHOR]

Objective: Prenatal screening with cell-free DNA (cfDNA) offers improved detection of Down syndrome (T21) compared to conventional screening. These tests are expensive and have fewer detectable anomalies. Our objective was to investigate potential costs and test performance of screening algorithms when accounting for detectable aneuploidies.Methods: This is a cost analysis for a large military treatment facility. Using a theoretical delivery cohort and published performance data, universal screening with cfDNA was compared to sequential screening, comparing T21 to all detectable aneuploidies. Predicted test performance and costs were calculated.Results: A cohort of 3000 deliveries was used. For T21, universal cfDNA is more expensive ($1,346,064) than sequential screening ($244,885), but has a lower false positive rate and avoids 101 invasive diagnostic tests. An additional case of T21 is detected with a marginal cost of $1,101,179. For all detectable aneuploidies, cfDNA is more expensive ($1,353,660) than sequential screening ($239,189), and 59 invasive diagnostic tests are avoided. Sequential screening detects an additional case of aneuploidy, with a cost savings of $1,114,471.Conclusions: Although cfDNA is superior in detecting T21 cases, sequential screening is superior when considering all aneuploidies detectable. The cost increase with universal cfDNA is significant, and is not justified with small improvements in the performance. [ABSTRACT FROM AUTHOR]

Background: The availability of non-invasive prenatal testing (NIPT) for aneuploidies is expanding rapidly throughout the world. Training health professionals to offer NIPT in a way that supports informed choice is essential for implementation. The aim of this study was to develop and evaluate a training package for health professionals to support the introduction of NIPT into clinical practice.Methods: Training on NIPT was offered to health professionals, primarily midwives, involved in Down syndrome screening and testing in eight hospitals located in England and Scotland as part of a research study evaluating the implementation of NIPT in the UK National Health Service. Training was evaluated using a mixed methods approach that included quantitative questionnaires at three time points and post-training qualitative interviews. The questionnaires measured confidence, self-perceived knowledge and actual knowledge about NIPT for Down syndrome. Interviews explored opinions about the training and experiences of offering NIPT.Results: The training provided to the health professionals was found to positively impact on their confidence in discussing NIPT with women in their clinic, and both their perceived and actual knowledge and understanding of NIPT was improved. Knowledge remained weak in four areas; cell-free fetal DNA levels increase with gestation; turnaround time for NIPT results; cell-free fetal DNA is placental in origin; and NIPT false positive rate.Conclusions: Training materials, including a lesson plan, PowerPoint presentation and written factsheet on NIPT, have been developed and evaluated for use in educating midwives and supporting the introduction of NIPT. Implementation of training should include a greater focus on the areas where knowledge remained low. Some groups of midwives will need additional training or support to optimise their confidence in discussing NIPT with women. [ABSTRACT FROM AUTHOR]

Background: As prenatal screening for fetal aneuploidy and neural tube defects evolves technologically and becomes increasingly utilized worldwide, an evaluation of the available evidence on women’s experiences with prenatal screening is warranted. Aims: To conduct an integrative review to enhance understanding of women’s experiences with prenatal screening for fetal aneuploidy and neural tube defects. Design: Systematic literature searches from January 2005 through January 2016, using the CINAHL, PubMed, and PsychInfo electronic databases and ancestry searches of included studies were performed to identify previously published, peer-reviewed quantitative and qualitative studies. Review methods: The integrative review method as proposed by Whittemore and Knafl was selected. Results: Thirty-nine studies were included in the review. The literature reveals that prenatal screening occurs in a complex social, ethical, and political reality. A theme of paradox emerged indicating the incongruity between reported and perceived risk, the tension between informational utility and moral decisions concerning pregnancy management, and the pervasive influences of authoritative and experiential knowledge. Conclusion: There is a need for future inquiry to critically examine the interrelationships of individual, biomedical, ethical, and sociopolitical factors surrounding prenatal screening. [ABSTRACT FROM PUBLISHER]

Minimally Invasive Karyotyping (MINK) was communicated in 2009 as a novel method for the non-invasive detection of fetal copy number anomalies in maternal plasma DNA. The original manuscript illustrated the potential of MINK using a model system in which fragmented genomic DNA obtained from a trisomy 21 male individual was mixed with that of his karyotypically normal mother at dilutions representing fetal fractions found in maternal plasma. Although it has been previously shown that MINK is able to non-invasively detect fetal microdeletions, its utility for aneuploidy detection in maternal plasma has not previously been demonstrated. The current study illustrates the ability of MINK to detect common aneuploidy in early gestation, compares its performance to other published third party methods (and related software packages) for prenatal aneuploidy detection and evaluates the performance of these methods across a range of sequencing read inputs. Plasma samples were obtained from 416 pregnant women between gestational weeks 8.1 and 34.4. Shotgun DNA sequencing was performed and data analyzed using MINK RAPIDR and WISECONDOR. MINK performed with greater accuracy than RAPIDR and WISECONDOR, correctly identifying 60 out of 61 true trisomy cases, and reporting only one false positive in 355 normal pregnancies. Significantly, MINK achieved accurate detection of trisomy 21 using just 2 million aligned input reads, whereas WISECONDOR required 6 million reads and RAPIDR did not achieve complete accuracy at any read input tested. In conclusion, we demonstrate that MINK provides an analysis pipeline for the detection of fetal aneuploidy in samples of maternal plasma DNA. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to validate noninvasive prenatal testing (NIPT) for fetal aneuploidies by whole-genome massively parallel sequencing (MPS).Methods: MPS was performed on cell-free DNA (cfDNA) isolated from maternal plasma in two groups: a first set of 186 euploid samples and a second set of 195 samples enriched of aneuploid cases (n = 69); digital PCR for fetal fraction (FF) assessment was performed on 178/381 samples. Cases with <10 × 106 reads (n = 54) were excluded for downstream data analysis. Follow-up data (invasive testing results or neonatal information) were available for all samples. Performances in terms of specificity/sensitivity and Z-score distributions were evaluated.Results: All positive samples for trisomy 21 (T21) (n = 43), trisomy 18 (T18) (n = 6) and trisomy 13 (T13) (n = 7) were correctly identified (sensitivity: 99.9%); 5 false positive results were reported: 3 for T21 (specificity = 98.9%) and 2 for T13 (specificity = 99.4%). Besides FF, total cfDNA concentration seems another important parameter for MPS, since it influences the number of reads.Conclusions: The overall test accuracy allowed us introducing NIPT for T21, T18 and T13 as a clinical service for pregnant women after 10 + 4 weeks of gestation. Sex chromosome aneuploidy assessment needs further validation due to the limited number of aneuploid cases in this study. [ABSTRACT FROM AUTHOR]

We evaluated performance characteristics of a laboratory-developed, non-invasive prenatal screening (NIPS) assay for fetal aneuploidies. This assay employs massively parallel shotgun sequencing with full automation. GC sequencing bias correction and statistical smoothing were performed to enhance discrimination of affected and unaffected pregnancies. Maternal plasma samples from pregnancies with known aneuploidy status were used for assay development, verification, and validation. Assay verification studies using 2,085 known samples (1873 unaffected, 69 trisomy 21, 20 trisomy 18, 17 trisomy 13) demonstrated complete discrimination between autosomal trisomy (Z scores >8) and unaffected (Z scores <4) singleton pregnancies. A validation study using 552 known samples (21 trisomy 21, 10 trisomy 18, 1 trisomy 13) confirmed complete discrimination. Twin pregnancies showed similar results. Follow-up of abnormal results from the first 10,000 clinical samples demonstrated PPVs of 98% (41/42) for trisomy 21, 92% (23/25) for trisomy 18, and 69% (9/13) for trisomy 13. Adjustment for causes of false-positive results identified during clinical testing (eg, maternal duplications) improved PPVs to 100% for trisomy 21 and 96% for trisomy 18. This NIPS test demonstrates excellent discrimination between trisomic and unaffected pregnancies. The PPVs obtained in initial clinical testing are substantially higher than previously reported NIPS methods. [ABSTRACT FROM AUTHOR]

Objective: Atrioventricular septal defect is associated with a high risk of a chromosomal abnormality, particularly trisomy 21. The aim of this study is to assess the rate of trisomy 21 in fetuses diagnosed with an atrioventricular septal defect and to examine the influence of prior screening on the rate of trisomy 21.Methods: Electronic ultrasound database was searched to identify fetuses diagnoses with an atrioventricular septal defect from 2002 to 2014. Rate of trisomy 21 and other aneuploidies was calculated among fetuses with normal situs. The prevalence of trisomy 21 and other aneuploidies was assessed in women with low and high first trimester risk for trisomy 21, using a cut-off value of 1:150 and 1:250.Results: A total 110 fetuses with a diagnosis of atrioventricular septal defect were identified. Among the 98 fetuses with normal situs, the prevalence of trisomy 21 was 46% (95% CI: 36-56%). Using a 1:150 threshold, the rate of trisomy 21 within the low-risk group was 41% (95% CI: 27-57%) while in the high-risk group it was 70% (95% CI: 52-83%), significantly higher than in the low risk group (p=0.028). Similar results were obtained when the 1:250 threshold was applied (66% versus 41%, p=0.055).Conclusions: The rate of trisomy 21 among fetuses identified with an atrioventricular septal defect in the second trimester is high even in those that undergo first trimester combined screening. Some fetuses with a high-risk screening result show a normal karyotype. Therefore, an offer of an invasive procedure to check fetal karyotyping is indicated. Knowledge of these rates may be helpful for parents in the decision making process. [ABSTRACT FROM AUTHOR]

Previous studies have demonstrated the influence of changes in the age at which women give birth, and of developments in prenatal screening and diagnosis on the number of pregnancies diagnosed and terminated with chromosomal anomalies. However, we are unaware of any population studies examining pregnancy terminations after diagnosis of chromosomal anomalies that has included all aneuploidies and the influence of maternal factors. The aims of this study were to examine the association between results of prenatal tests and pregnancy termination, and the proportion of foetuses with and without chromosomal anomalies referred for invasive diagnostic tests over time. Diagnostic information of 26,261 prenatal invasive tests from all genetic service laboratories in Scotland from 2000 to 2011 was linked to Scottish Morbidity Records to obtain details on pregnancy outcome. Binary logistic regression was carried out to test the associations of year and type of diagnosis with pregnancy termination, while controlling for maternal age, neighbourhood deprivation and parity. There were 24,155 (92.0%) with no chromosomal anomalies, 1,483 (5.6%) aneuploidy diagnoses, and 623 (2.4%) diagnoses of anomaly that was not aneuploidy (including translocations and single chromosome deletions). In comparison with negative test results, pregnancies diagnosed with trisomy were most likely to be terminated (adjusted OR 437.40, 95% CI 348.19–549.46) followed by other aneuploid anomalies (adjusted OR 95.94, 95% CI 69.21–133.01). During the study period, fewer pregnancies that were diagnosed with aneuploidy were terminated, including trisomy diagnoses (adjusted OR 0.44, 95% CI 0.26–0.73). Older women were less likely to terminate (OR 0.35, 95% CI 0.28, 0.42), and parity was also an independent predictor of termination. In keeping with previous findings, while the number of invasive diagnostic tests declined, the proportion of abnormal results increased from 6.09% to 10.88%. Systematic advances in prenatal screening have improved detection rates for aneuploidy. This has been accompanied by a reduction in the rate of termination for aneuploidy. This may reflect societal changes with acceptance of greater diversity, but this is speculation, and further research would be needed to test this. [ABSTRACT FROM AUTHOR]

Objective: First, to assess what was the uptake of cell free DNA (cfDNA) testing after a combined test and the maternal and fetal factors that influenced this decision, and second, to assess the uptake and factors that influence the choice of invasive testing.Methods: This observational retrospective study included 1083 singleton pregnancies who had a combined test for screening for Down syndrome between 11 (+) (0) and 13 (+) (6) weeks. Multivariate logistic regression analysis was used to determine which factors affected the uptake of cfDNA test and invasive testing among risk for trisomies 21, 18, and 13, maternal characteristics and fetal nuchal translucency (NT) thickness.Results: Two-hundred fifty-seven (23.7%) women had a cfDNA test, 89 (8.2%) had an invasive test, and 737 (68.1%) had no further test. The uptake of cfDNA increased with the risk for trisomies (p < 0.001), maternal age (p = 0.013), and was higher in nulliparous women (p = 0.004). The uptake of invasive test increased with the risk for trisomies (p < 0.001) and NT thickness (p < 0.001).Conclusions: This study shows that the uptake of cfDNA testing increases with the risk for trisomies, maternal age, and is higher in nulliparous, whereas the uptake of invasive testing increases with the risk for trisomies and NT thickness. [ABSTRACT FROM AUTHOR]

Cell-free fetal DNA testing is being used in parallel or in contingency screening as part of the first trimester screen. The test has high sensitivity and specificity for the trisomies 21, 18 and 13. The test also offers the option of assessing sex chromosome aneuploidies (SCA) which are recognised to be the next most common group of aneuploidies in the live birth population. Companies that offer the sex chromosome assessment report an accuracy rate of above 99% and a significant number of high-risk results have been detected in a multi-site Australian ultrasound practice. A high proportion of these women underwent prenatal testing to further assess the sex chromosomes. This study reports the results of these invasive investigations and results show that many of the high-risk SCA results appear to be false positives. This study reports the clinical experience of cell-free fetal DNA (cfDNA) testing with regard to sex chromosome aneuploidies in singleton pregnancies for a multi-site Sydney specialist O&G Ultrasound practice. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to investigate the effect of diurnal variation on biochemical results of first trimester aneuploidy screening test.Methods: A total of 2725 singleton pregnant female, who had normal fetal nuchal translucency (NT) thickness, were included in the study during this period. Individuals were divided into two groups according to the sampling time (morning group: 09:00-11:00 am and afternoon group: 02:00-04:00 pm). Hormonal parameters (free-beta human chorionic gonadotropin [free β-hCG] and pregnancy-associated plasma protein-A [PAPP-A] multiples of median [MoM] levels) of first trimester (11(+0)-13(+6) weeks) combined aneuploidy screening test were compared between morning and afternoon groups.Results: PAPP-A MoM levels were significantly lower in the afternoon group when compared to the morning group (p = 0.001), whereas free β-hCG MoM levels were similar in the both groups (p = 0.392). Rate of high risk for Down syndrome (Combine risk >1/300) and amniocentesis ratio were found higher in the afternoon group than morning group, but there were no difference between groups for the number of fetuses with Down syndrome.Conclusion: Receiving the venous blood sample for first trimester aneuploidy screening test in the afternoon causes low PAPP-A MoM levels. [ABSTRACT FROM AUTHOR]

Objective: The clinical utilization of non-invasive prenatal testing (NIPT) for identification of fetal aneuploidies is expanding worldwide. The aim of this study was to gain an increased understanding of pregnant women’s awareness, attitudes, preferences for risk information and decision-making concerning prenatal examinations with emphasis on NIPT, before its introduction into Swedish healthcare. Method: Pregnant women were recruited to fill in a questionnaire, including multiple-choice questions and Likert scales, at nine maternity clinics located in different areas of Stockholm, Sweden. Results: In total, 1,003 women participated in the study (86% consent rate). The vast majority (90.7%) considered examinations aiming to detect fetal abnormalities to be good. Regarding NIPT, 59.8% stated that they had heard about the method previously, yet 74.0% would like to use the test if available. The main factor affecting the women’s decision to undergo prenatal chromosomal screening was worry about the baby’s health (82.5%), followed by the urge to have as much information as possible about the fetus (54.5%). Most women (79.9%) preferred to receive NIPT information orally. Conclusion: The overwhelming majority of a cohort of 1,003 pregnant women considered prenatal examinations good. Moreover, the majority had a positive attitude towards NIPT and would like to use the test if available. [ABSTRACT FROM AUTHOR]