Clinical experience from Thailand: noninvasive prenatal testing as screening tests for trisomies 21, 18 and 13 in 4736 pregnancies

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).

Economic evaluation of prenatal screening for fetal aneuploidies in Thailand

Historically, there has been a lack of cost-effectiveness data regarding the inclusion of universal non-invasive prenatal testing (NIPT) for trisomy 21, 18, and 13 in the benefit package of the Universal Health Coverage (UHC) in Thailand. Therefore, this study aimed to perform the cost-benefit analysis of prenatal screening tests and calculate the budget impact that would result from the implementation of a universal NIPT program. A decision-tree model was employed to evaluate cost and benefit of different prenatal chromosomal abnormalities screenings: 1) first-trimester screening (FTS), 2) NIPT, and 3) definitive diagnostic (amniocentesis). The comparison was made between these screenings and no screening in three groups of pregnant women: all ages, < 35 years, and ≥ 35 years. The analysis was conducted from societal and governmental perspectives. The costs comprised direct medical, direct non-medical, and indirect costs, while the benefit was cost-avoidance associated with caring for children with trisomy and the loss of productivity for caregivers. Parameter uncertainties were evaluated through one-way and probabilistic sensitivity analyses. From a governmental perspective, all three methods were found to be cost-beneficial. Among them, FTS was identified as the most cost-beneficial, especially for pregnant women aged ≥ 35 years. From a societal perspective, the definitive diagnostic test was not cost-effective, but the other two screening tests were. The most sensitive parameters for FTS and NIPT strategies were the productivity loss of caregivers and the incidence of trisomy 21. Our study suggested that NIPT was the most cost-effective strategy in Thailand, if the cost was reduced to 47 USD. This evidence-based information can serve as a crucial resource for policymakers when making informed decisions regarding the allocation of resources for prenatal care in Thailand and similar context.

The accuracy and feasibility of noninvasive prenatal testing in a consecutive series of 20,626 pregnancies with different clinical characteristics

Background

To evaluate the accuracy and feasibility of noninvasive prenatal testing (NIPT) according to the results of NIPT and pregnancy outcomes with different indications.

Methods

Between October 2014 and December 2020, 20,626 pregnant women who received NIPT were included in this study. The positive predictive value (PPV) of trisomy 21, 18, and 13 (T21, T18, T13), sex chromosome abnormalities (SCAs), other chromosomal aneuploidies, and chromosomal microdeletion/microduplication were calculated. The positive results of NIPT were confirmed by amniocentesis, Karyotype analysis, and chromosome microarray analysis (CMA).

Results

In total, 263 positive cases (263/20,626, 1.28%) were detected by NIPT, of which T21, T18, and T13 were 69, 26, and 9 cases, respectively. Sex chromosome abnormalities (SCAs), other chromosomal aneuploidies, and copy number variants (CNVs) were 69, 12, and 38 cases, respectively. There were true positive in 49 of T21, 13 of T18, 1 of T13, 32 of SCAs, 1 of other chromosomal aneuploidies, and 15 of CNVs. The NIPT sensitivity of T21, T18, T13, SCAs, other chromosomal aneuploidies, and CNVs was all 100%, the specialty was 99.90%, 99.94%, 99.96%, 99.82%, 99.95%, 99.89%, and the PPV was 71.01%, 50.00%, 11.11%, 46.38%, 8.33%, 39.47%, respectively. The PPV was high in T21, moderate in T18 and SCAs, and low in T13 and other chromosomal abnormalities.

Conclusion

NIPT has high accuracy, specificity and and can effectively avoid the occurrence of birth defects, but it cannot replace prenatal diagnosis. The accuracy, specificity, and sensitivity of NIPT in detecting sex chromosomes, chromosome microdeletion/microduplication, and other chromosomal abnormalities should be improved.

A Critical Evaluation of Validation and Clinical Experience Studies in Non-Invasive Prenatal Testing for Trisomies 21, 18, and 13 and Monosomy X

Non-invasive prenatal testing (NIPT) for trisomies 21, 18, 13 and monosomy X is widely utilized with massively parallel shotgun sequencing (MPSS), digital analysis of selected regions (DANSR), and single nucleotide polymorphism (SNP) analyses being the most widely reported methods. We searched the literature to find all NIPT clinical validation and clinical experience studies between January 2011 and January 2022. Meta-analyses were performed using bivariate random-effects and univariate regression models for estimating summary performance measures across studies. Bivariate meta-regression was performed to explore the influence of testing method and study design. Subgroup and sensitivity analyses evaluated factors that may have led to heterogeneity. Based on 55 validation studies, the detection rate (DR) was significantly higher for retrospective studies, while the false positive rate (FPR) was significantly lower for prospective studies. Comparing the performance of NIPT methods for trisomies 21, 18, and 13 combined, the SNP method had a higher DR and lower FPR than other methods, significantly so for MPSS, though not for DANSR. The performance of the different methods in the 84 clinical experience studies was consistent with validation studies. Clinical positive predictive values of all NIPT methods improved over the last decade. We conclude that all NIPT methods are highly effective for fetal aneuploidy screening, with performance differences across methodologies.

Next-generation sequencing: a follow-up of 36,913 singleton pregnancies with noninvasive prenatal testing in central China

PURPOSE

To evaluate the noninvasive prenatal testing (NIPT) results of 36,913 cases in Jiangxi province of central China and explore its application value in prenatal screening and diagnosis.

METHODS

This retrospective analysis included 36,913 singleton pregnant women who underwent NIPT because of moderate-/high-risk pregnancy or voluntary requirements between January 2017 and December 2019 in our hospital. Chromosomal abnormalities such as trisomies 21, 18, and 13 (T21, T18, T13) and sex chromosome aneuploidies (SCAs) were judged by standard Z-score analysis. Positive NIPT results were confirmed by amniocentesis and karyotyping. Pregnancy outcomes were followed up via telephone interview.

RESULTS

A total of 1.01% (371/36,913) positive cases were detected by NIPT, comprising 137, 46, 31, and 157 cases of T21, T18, T13, and SCAs, respectively. A total of 116 of T21, 27 of T18, 13 of T13, and 51 of SCAs were confirmed to be true positive; all normal cases that had been followed up were verified to be true negative. The NIPT sensitivity in T21, T18, T13, and SCAs was 100.00% individually, whereas the specificity was 99.94% (36,488/36,509), 99.95% (36,579/36,598), 99.95% (36,594/36,612), and 99.72% (36,472/36,574), respectively. Furthermore, the negative predictive values of T21, T18, T13, and SCAs were all 100%, while the positive predictive values were 84.67%, 58.70%, 41.94%, and 33.33%, respectively.

CONCLUSION

NIPT is highly sensitive and has a low false positive rate in testing clinically significant fetal aneuploidies of general reproductive women. However, this technique cannot substitute for amniocentesis and karyotyping, and detailed genetic counseling is also essential for the high-risk group of NIPT.

A retrospective analysis the clinic data and follow-up of non-invasive prenatal test in detection of fetal chromosomal aneuploidy in more than 40,000 cases in a single prenatal diagnosis center

OBJECTIVE

To evaluate the efficacy of non-invasive prenatal test (NIPT) in the detection of chromosomal aneuploidy according to the follow-up information from a single prenatal diagnosis center.

METHODS

A total of 40,311 cases were retrospectively reviewed. The screening was performed using a BGI protocol, pre-test and post-test genetic counseling was provided, and the pregnancy outcomes were recorded. The results of NIPT and clinical follow-up data were analyzed together with the pregnancy outcomes, confirmatory testing results, and ultrasound findings.

RESULTS

Of the 40,311cases were includes in the study, successful follow-up was conducted in 468 (1.16%) cases with high risk, 225 (0.56%) cases with rare autosomal trisomy (RAT) and copy number variation (CNV). 39,572 (98.17%) cases with low risk and 623 (1.57%) cases of which were confirmed with adverse pregnancy outcomes. 46 (0.1%) cases with failed tests. Among them, 398 (84.7%) cases with high-risk results chose invasive testing, revealing 198 true positive cases. In cases with RAT and CNV results, 189 cases underwent invasive testing, revealing 5 cases RAT and 4 pathogenic CNVs.

CONCLUSIONS

NIPT appears to be effective in detecting the fetal chromosomal aneuploidies T21, T18 and SCAs, but it exist false positive/negative cases, unconfirmed high-risk cfDNA results, and the high false positive rate in cases with RAT and CNV results implied the limitations of this screening method. Our study showed the importance to associate cfDNA screening results with clinical follow-up data and provided information that may help with result interpretation, genetic counseling and the decision making in clinic.

The Clinical Utility of Non-invasive Prenatal Testing for Pregnant Women With Different Diagnostic Indications

Background

Our aim was to evaluate the clinical utility of non-invasive prenatal testing for pregnant women with different diagnostic indications.

Methods

In eight counties and districts of Yancheng, we studied 13,149 pregnant women with different indications who were offered NIPT for fetal screening, including for sex chromosomal aneuploidies (SCAs), rare autosomal trisomies (RATs), and subchromosomal copy number variations (CNVs). The purpose was to compare the detection of positive predictive values (PPVs) of different indications with the use of NIPT. The results were validated by karyotyping, chromosomal microarray analysis (CMA), or follow-up of pregnancy outcomes.

Results

13,149 maternal plasma samples were sequenced, among which 28 samples (0.2%) failed the sequencing quality control. The remaining 13,121 samples were analyzed, and birth follow-up missed 2,192 samples (16.7%). The PPVs of NIPT results for trisomy 21 (T21) and trisomy 18 (T18) and SCAs were 96.67, 63.64, and 31.34%, respectively. Among the advanced maternal age (AMA), serum screening high risk (SSHR), serum screening intermediate risk (SSIR), and voluntary screening (VS) groups, the PPVs for the common trisomies were 81.25, 85.71, 100, and 70%, respectively; the PPVs for total chromosomal abnormalities were 55.82, 65.22, 23.08, and 36.59%, respectively.

Conclusion

NIPT for T21 and T18 and SCAs screening were ideal, and the PPVs for trisomy 13 (T13), RATs, and CNVs were low. For the AMA and VS groups, NIPT could be used as a first-line screening program; for SSHR and SSIR groups, NIPT could be used as a second-line supplementary screening program.

Clinical performance of DNA-based prenatal screening using single-nucleotide polymorphisms approach in Thai women with singleton pregnancy

Background

To review the performance of noninvasive prenatal screening (NIPS) using targeted single‐nucleotide polymorphisms (SNPs) approach in mixed‐risk Thai women.

Methods

Retrospective analysis of data for detection of trisomy 21 (T21), 18 (T18), 13 (T13), monosomy X (XO), other sex chromosome aneuploidies (SCA), and triploidy/vanishing twins (VT) from a single commercial laboratory.

Results

Mean (±SD) gestational age and maternal weight were 13.2 (±2.1) weeks and 125.7 (±22.4) pounds, respectively (n = 8,572). From 462/8,572 (5.4%) no‐calls; 1/462 (0.2%) was uninformative SNPs, and 1/462 chose amniocentesis. Redraw settled 323/460 (70%) samples with low fetal fraction (FF); and 8,434/8,572 (98.4%) were finally reportable, with 131 high risks (1.6%). The median (min‐max) FF of reportable (n = 8,434) and unreportable samples (n = 137) samples were 10.5% (2.6–37.9) and 3.8% (1–14.1), respectively (p < .05). Fetal karyotypes were available in 106/131 (80.9%) and 52/138 (37.7%) high risk and repeated no‐calls, respectively. The positive predictive values (PPVs) for T21 (n = 47), T18 (n = 15), T13 (n = 7), XO (n = 8), other SCA (n = 7), and triploidy/VT were 94%, 100%, 58.3%, 66.7%, 70%, and 57.1%, respectively. None of repeated no‐calls had aneuploidies.

Conclusion

SNP‐based NIPS has high PPVs for T21 and T18. Although the proprietary SNPs library is not population‐specific, uninformative SNPs are uncommon.

A contingent model for cell-free DNA testing to detect fetal aneuploidy after first trimester combined screening

Objective

To assess the results of the first trimester combined test to design a prenatal protocol for the introduction of the cell-free fetal DNA test as a contingent screening model.

Method

An observational retrospective study in 12,327 singleton pregnancies to analyze the results of the combined first trimester screening, the nuchal translucency ≥97.5 percentile, their cytogenetic results and birth outcomes.

Results

A total of 533 (4.3%) pregnant women had a risk in combined first trimester screening above 1/300. In this group, sixty nine had an unbalanced karyotype. The abnormal/normal karyotype ratio was 1/28 in pregnant women with intermediate risk (1/51-1/300) for trisomy 21 and trisomy 18, 1/58 with intermediate risk just for trisomy 21 and 1/37 with intermediate risk just for trisomy 18. A 19.8% of the unbalanced karyotypes had chromosomal abnormalities other than trisomies 21, 18 and 13. Two false negatives cases at first trimester combined screening presented a nuchal translucency ≥ p97.5^th.

Conclusion

We propose the introduction of the cell-free fetal DNA test when the risk of first trimester combined screening is intermediate (1/51–1/300) and when nuchal translucency is ≥ p97.5^th with a low risk in the combined screening. This policy would allow us to continue to detect uncommon chromosomal abnormalities.

Sequential combined test, second trimester maternal serum markers, and circulating fetal cells to select women for invasive prenatal diagnosis

From January 1^st 2013 to August 31^st 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.

Genomics-based non-invasive prenatal testing for detection of fetal chromosomal aneuploidy in pregnant women

BACKGROUND

Common fetal aneuploidies include Down syndrome (trisomy 21 or T21), Edward syndrome (trisomy 18 or T18), Patau syndrome (trisomy 13 or T13), Turner syndrome (45,X), Klinefelter syndrome (47,XXY), Triple X syndrome (47,XXX) and 47,XYY syndrome (47,XYY). Prenatal screening for fetal aneuploidies is standard care in many countries, but current biochemical and ultrasound tests have high false negative and false positive rates. The discovery of fetal circulating cell-free DNA (ccfDNA) in maternal blood offers the potential for genomics-based non-invasive prenatal testing (gNIPT) as a more accurate screening method. Two approaches used for gNIPT are massively parallel shotgun sequencing (MPSS) and targeted massively parallel sequencing (TMPS).

OBJECTIVES

To evaluate and compare the diagnostic accuracy of MPSS and TMPS for gNIPT as a first-tier test in unselected populations of pregnant women undergoing aneuploidy screening or as a second-tier test in pregnant women considered to be high risk after first-tier screening for common fetal aneuploidies. The gNIPT results were confirmed by a reference standard such as fetal karyotype or neonatal clinical examination.

SEARCH METHODS

We searched 13 databases (including MEDLINE, Embase and Web of Science) from 1 January 2007 to 12 July 2016 without any language, search filter or publication type restrictions. We also screened reference lists of relevant full-text articles, websites of private prenatal diagnosis companies and conference abstracts.

SELECTION CRITERIA

Studies could include pregnant women of any age, ethnicity and gestational age with singleton or multifetal pregnancy. The women must have had a screening test for fetal aneuploidy by MPSS or TMPS and a reference standard such as fetal karyotype or medical records from birth.

DATA COLLECTION AND ANALYSIS

Two review authors independently carried out study selection, data extraction and quality assessment (using the QUADAS-2 tool). Where possible, hierarchical models or simpler alternatives were used for meta-analysis.

MAIN RESULTS

Sixty-five studies of 86,139 pregnant women (3141 aneuploids and 82,998 euploids) were included. No study was judged to be at low risk of bias across the four domains of the QUADAS-2 tool but applicability concerns were generally low. Of the 65 studies, 42 enrolled pregnant women at high risk, five recruited an unselected population and 18 recruited cohorts with a mix of prior risk of fetal aneuploidy. Among the 65 studies, 44 evaluated MPSS and 21 evaluated TMPS; of these, five studies also compared gNIPT with a traditional screening test (biochemical, ultrasound or both). Forty-six out of 65 studies (71%) reported gNIPT assay failure rate, which ranged between 0% and 25% for MPSS, and between 0.8% and 7.5% for TMPS.In the population of unselected pregnant women, MPSS was evaluated by only one study; the study assessed T21, T18 and T13. TMPS was assessed for T21 in four studies involving unselected cohorts; three of the studies also assessed T18 and 13. In pooled analyses (88 T21 cases, 22 T18 cases, eight T13 cases and 20,649 unaffected pregnancies (non T21, T18 and T13)), the clinical sensitivity (95% confidence interval (CI)) of TMPS was 99.2% (78.2% to 100%), 90.9% (70.0% to 97.7%) and 65.1% (9.16% to 97.2%) for T21, T18 and T13, respectively. The corresponding clinical specificity was above 99.9% for T21, T18 and T13.In high-risk populations, MPSS was assessed for T21, T18, T13 and 45,X in 30, 28, 20 and 12 studies, respectively. In pooled analyses (1048 T21 cases, 332 T18 cases, 128 T13 cases and 15,797 unaffected pregnancies), the clinical sensitivity (95% confidence interval (CI)) of MPSS was 99.7% (98.0% to 100%), 97.8% (92.5% to 99.4%), 95.8% (86.1% to 98.9%) and 91.7% (78.3% to 97.1%) for T21, T18, T13 and 45,X, respectively. The corresponding clinical specificities (95% CI) were 99.9% (99.8% to 100%), 99.9% (99.8% to 100%), 99.8% (99.8% to 99.9%) and 99.6% (98.9% to 99.8%). In this risk group, TMPS was assessed for T21, T18, T13 and 45,X in six, five, two and four studies. In pooled analyses (246 T21 cases, 112 T18 cases, 20 T13 cases and 4282 unaffected pregnancies), the clinical sensitivity (95% CI) of TMPS was 99.2% (96.8% to 99.8%), 98.2% (93.1% to 99.6%), 100% (83.9% to 100%) and 92.4% (84.1% to 96.5%) for T21, T18, T13 and 45,X respectively. The clinical specificities were above 100% for T21, T18 and T13 and 99.8% (98.3% to 100%) for 45,X. Indirect comparisons of MPSS and TMPS for T21, T18 and 45,X showed no statistical difference in clinical sensitivity, clinical specificity or both. Due to limited data, comparative meta-analysis of MPSS and TMPS was not possible for T13.We were unable to perform meta-analyses of gNIPT for 47,XXX, 47,XXY and 47,XYY because there were very few or no studies in one or more risk groups.

AUTHORS' CONCLUSIONS

These results show that MPSS and TMPS perform similarly in terms of clinical sensitivity and specificity for the detection of fetal T31, T18, T13 and sex chromosome aneuploidy (SCA). However, no study compared the two approaches head-to-head in the same cohort of patients. The accuracy of gNIPT as a prenatal screening test has been mainly evaluated as a second-tier screening test to identify pregnancies at very low risk of fetal aneuploidies (T21, T18 and T13), thus avoiding invasive procedures. Genomics-based non-invasive prenatal testing methods appear to be sensitive and highly specific for detection of fetal trisomies 21, 18 and 13 in high-risk populations. There is paucity of data on the accuracy of gNIPT as a first-tier aneuploidy screening test in a population of unselected pregnant women. With respect to the replacement of invasive tests, the performance of gNIPT observed in this review is not sufficient to replace current invasive diagnostic tests.We conclude that given the current data on the performance of gNIPT, invasive fetal karyotyping is still the required diagnostic approach to confirm the presence of a chromosomal abnormality prior to making irreversible decisions relative to the pregnancy outcome. However, most of the gNIPT studies were prone to bias, especially in terms of the selection of participants.

Prospective study of the feasibility and effectiveness of a second-trimester quadruple test for Down syndrome in Thailand

OBJECTIVE

To evaluate the feasibility and effectiveness of a quadruple test for Down syndrome in the second trimester of pregnancy in clinical settings in Thailand.

METHODS

From October 2015 to September 2016, a prospective study was undertaken in 19 hospitals in Songkhla province, Thailand. Women with a singleton pregnancy of 14-18 weeks were enrolled and underwent the quadruple test. The risk cutoff value was set at 1:250. All women with a positive test (risk ≥1:250) were offered amniocentesis. Women were followed up until delivery.

RESULTS

Among 2375 women, 206 (8.7%) had a positive quadruple test; 98 (47.6%) of these women voluntarily underwent amniocentesis. Overall, seven pregnancies were complicated with chromosomal abnormalities (2.9 cases in 1000), including four cases of Down syndrome (1.7 in 1000) and three of other abnormalities. The detection, false-positive, and accuracy rates of the quadruple test for Down syndrome were 75.0%, 8.6%, and 91.4%, respectively.

CONCLUSION

The quadruple test was found to be a feasible and efficient method for screening for Down syndrome in the second trimester of pregnancy in a Thai clinical setting. The test should be performed for pregnant women before an invasive test for Down syndrome.

Noninvasive prenatal screening for fetal common sex chromosome aneuploidies from maternal blood

Objective

To explore the feasibility of high-throughput massively parallel genomic DNA sequencing technology for the noninvasive prenatal detection of fetal sex chromosome aneuploidies (SCAs).

Methods

The study enrolled pregnant women who were prepared to undergo noninvasive prenatal testing (NIPT) in the second trimester. Cell-free fetal DNA (cffDNA) was extracted from the mother’s peripheral venous blood and a high-throughput sequencing procedure was undertaken. Patients identified as having pregnancies associated with SCAs were offered prenatal fetal chromosomal karyotyping.

Results

The study enrolled 10 275 pregnant women who were prepared to undergo NIPT. Of these, 57 pregnant women (0.55%) showed fetal SCA, including 27 with Turner syndrome (45,X), eight with Triple X syndrome (47,XXX), 12 with Klinefelter syndrome (47,XXY) and three with 47,XYY. Thirty-three pregnant women agreed to undergo fetal karyotyping and 18 had results consistent with NIPT, while 15 patients received a normal karyotype result. The overall positive predictive value of NIPT for detecting SCAs was 54.54% (18/33) and for detecting Turner syndrome (45,X) was 29.41% (5/17).

Conclusion

NIPT can be used to identify fetal SCAs by analysing cffDNA using massively parallel genomic sequencing, although the accuracy needs to be improved particularly for Turner syndrome (45,X).