Noninvasive Prenatal Testing Results Research Articles

Evaluation of an automated process for disclosure of negative noninvasive prenatal test results.

We designed and implemented a novel automated negative non-invasive prenatal test (NIPT) result disclosure process using a proprietary, HIPAA-compliant web-based portal. High-risk pregnant patients who opted for NIPT from 04/2017 to 12/2018 were given the option to receive their negative result through the automated process. Patients were required to watch a brief educational video and answer evaluative questions before downloading their result. After completing the process, patients completed a survey regarding their opinion of the efficiency and convenience of the process and their satisfaction. A total of 10,170 women registered online during the study period, and 8,965 completed the automated process (88%). Out of 8,965 women, 2,121 women responded to the survey (24%). Most (2,030 of 2,101) strongly agreed/agreed that they could easily navigate the patient portal (97%); 1,852 of 1,966 strongly agreed/agreed that disclosure was efficient and convenient (94%); 1,852 of 1,960 strongly agreed/agreed that they felt informed after watching a short educational video (94%); and 1,903 of 1,967 strongly agreed/agreed that they preferred downloading results rather than waiting for their next doctor's appointment (97%). This study demonstrates high patient satisfaction with this automated and scalable solution in a high-volume health system. As the utilization of genetic testingincreases, we predict greater need for innovative healthcare delivery models.

The significance of trisomy 7 mosaicism in noninvasive prenatal screening

BackgroundThis study was an evaluation of the role of noninvasive prenatal testing (NIPT) in the detection of trisomy 7 in prenatal diagnosis.MethodA total of 35 consecutive cases underwent screening for trisomies by cell-free DNA testing between April 2015 and November 2017 due to suspicious NIPT results; these cases represented 0.11% of patients (35/31,250) with similar frequencies of abnormal results among the laboratories performing the tests. NIPT was offered to further screen for common fetal chromosomal abnormalities. Karyotype analysis, chromosomal microarray analysis (CMA), and next-generation sequencing (NGS) were used to detect 20, 14, and 25 patients, respectively, who accepted confirmatory diagnostic testing.ResultsHigh-risk results by NIPT were recorded for trisomy 7 alone in 29 women: dual aneuploidy in 4 patients and multiple aneuploidy in 2 patients. Karyotype analysis of amniotic fluid cells was normal in all 20 pregnancies, suggesting a probability of confined placental mosaicism. Further CMA data were obtained in 14 of the cases mentioned above, and 2 fetuses were detected with positive results with copy number variation. The NGS results suggested that all these samples were placental chimerisms of chromosome 7, except for one sample that was found to be an additional chimerism of chromosome 2, which was also consistent with the NIPT result.ConclusionOur results may be useful for the counseling of pregnant women in the detection of trisomy 7 by NIPT.

False positive non-invasive prenatal testing results due to vanishing twins

To explore the mechanism and duration of false positive results of non-invasive prenatal testing (NIPT) caused by vanishing twins. To detect the variation of cell-free fetal DNA fraction before and after the fetal death and explore its influence on the results of NIPT at different gestational weeks. Prenatal diagnosis was also carried out on amniotic fluid sample derived from the survivor twin. After birth, the two placentas and papyraceous fetus were obtained to ascertain the definitive genetic diagnosis and pathological changes through fluorescence in situ hybridization, fluorescence quantitative PCR and histopathological examination. Eight cases of vanishing twins leading to discordant NIPT results were reviewed for determining the duration of this influence. The vanishing twin has led to immediate flooding of cfDNA into the maternal plasma due to necrotic cytotrophoblasts, which in turn caused increased release of fetal DNA in a short time. However, this did not change the NIPT result for a period of time. The tissue and chorionic villi of perished fetus presented extensive degenerative necrosis. The false positive NIPT result caused by vanishing twins may be attributed to continuous release of DNA fragments into the maternal plasma by the fetuses. The influence of the vanished fetuses, which may lead to discordant NIPT results, can last for at least 7-8 weeks but no more than 12-14 weeks during the first and second trimester.

The performance of noninvasive prenatal testing (NIPT) in monochorionic diamniotic twin pregnancies with treatment of assisted reproductive techniques (ART)

Introduction The objective of this research is to study the performance of noninvasive prenatal testing (NIPT) in monochorionic diamniotic twin pregnancies after the treatment of assisted reproductive technology (ART). Material & methods From March 2015 to December 2016, we provided NIPT targeting trisomy 21 (T21), 18 (T18), and 13 (T13) by sequencing cell-free DNA in maternal plasma, for 2403 chinese pregnant women with monochorionic diamniotic twin pregnancies through ART treatment. Positive NIPT results were validated by karyotyping, while negative results were interviewed after delivery. Results In total of 2403 cases, NIPT had a failure rate of 1.8% (44/2403). 7 cases of T21 were identified by NIPT and confirmed by karyotyping or follow-up interviews, among which 3 were true-positive and 4 were false-positive, making a positive predictive value as 42%. Interestingly, all the 4 false-positive cases were vanishing twins while the 3 true-positive cases were not. 6 cases of T18 were identified by NIPT, among which 5 were false-positive and 1 aborted spontaneously. 4 in the 5 T18 false-positive cases were vanishing twins. Among 2346 cases with NIPT negative results, 2179 cases (92.9%) were confirmed by follow-up survey of postnatal phenotypes, while 111 cases (4.7%) had adverse pregnant outcomes with unconfirmed reasons. The remaining 56 cases (2.4%) refused follow-up interviews. No false negative result was reported. Conclusion Our data implies that NIPT for T21 and T18 has a notable rate of false-positive results, with vanishing twins as the major cause. Nonetheless, NIPT is still a good screening approach for ART monochorionic diamniotic twin pregnancies, as no false-positive case was observed in this study. The objective of this research is to study the performance of noninvasive prenatal testing (NIPT) in monochorionic diamniotic twin pregnancies after the treatment of assisted reproductive technology (ART). From March 2015 to December 2016, we provided NIPT targeting trisomy 21 (T21), 18 (T18), and 13 (T13) by sequencing cell-free DNA in maternal plasma, for 2403 chinese pregnant women with monochorionic diamniotic twin pregnancies through ART treatment. Positive NIPT results were validated by karyotyping, while negative results were interviewed after delivery. In total of 2403 cases, NIPT had a failure rate of 1.8% (44/2403). 7 cases of T21 were identified by NIPT and confirmed by karyotyping or follow-up interviews, among which 3 were true-positive and 4 were false-positive, making a positive predictive value as 42%. Interestingly, all the 4 false-positive cases were vanishing twins while the 3 true-positive cases were not. 6 cases of T18 were identified by NIPT, among which 5 were false-positive and 1 aborted spontaneously. 4 in the 5 T18 false-positive cases were vanishing twins. Among 2346 cases with NIPT negative results, 2179 cases (92.9%) were confirmed by follow-up survey of postnatal phenotypes, while 111 cases (4.7%) had adverse pregnant outcomes with unconfirmed reasons. The remaining 56 cases (2.4%) refused follow-up interviews. No false negative result was reported. Our data implies that NIPT for T21 and T18 has a notable rate of false-positive results, with vanishing twins as the major cause. Nonetheless, NIPT is still a good screening approach for ART monochorionic diamniotic twin pregnancies, as no false-positive case was observed in this study.

NIPT - POTENTIAL TOOL FOR PGT FOLLOW UP

Objective Invasive procedures such as amniocentesis and CVS, in combination with karyotyping or molecular testing, are currently used to confirm PGT results of transferred embryos. However, some couples who have achieved a pregnancy following PGT-M are reluctant to use this confirmatory approach even though the risk of miscarriage and infection associated with fetal cell sampling is low. In this study, we investigate noninvasive prenatal testing (NIPT) as an alternative tool for PGT-M follow up. Materials and Methods NIPT of the cell free fetal DNAwas performed for pregnancies at risk for a single gene disease using circulating single molecule amplification and re-sequencing technology (cSMART) to target the known parental mutations and genome-wide SNPs. Fetal genotypes were called based on the maternal plasma mutation ratios. Results In preliminary studies of naturally conceived pregnancies undergoing testing for autosomal recessive conditions, fetal genotypes predicted by cSMART assay were concordant with invasive results in 4 of 4 cases (100%) of Wilson disease, 18 of 18 cases (100%) of PKU, 73 of 80 cases (91%) of autosomal recessive hearing loss and 98 of 100 cases (98%) of beta thalassemia. There was a strong association of low fetal DNA fraction and poor quality plasma samples with discordant NIPT results. In a further study, we performed NIPT follow up for a complicated PGT-M case for Fanconi Anemia with HLA matching. The case involved a couple who were both carriers of an identical FANCG deletion mutation. Following embryo testing by mutation analysis and linked STR analysis, 2 HLA matched and disease free (normal and carrier) embryos were transferred, resulting in a twin pregnancy. At 15 weeks gestation, cSMART analysis of the pregnancy plasma determined fetal DNA fractions of 14.2% and 6.6% for twin 1 and 2, respectively. The maternal plasma FANCG mutation ratio was measured at 46.2% (50% minus half the fetal fraction of twin 2), which was consistent with the presence of a carrier fetus (twin 1) and a normal fetus (twin 2). Additional retrospective studies of the WGA products from the transferred embryos using single molecule sequencing also confirmed the FANCG genotypes of the transferred embryos and a HLA match to the sick sibling. Conclusions In proof of concept studies for autosomal recessive conditions, we demonstrate that NIPT can be successfully used to reliably and accurately determine fetal genotypes. NIPT has clinical utility as a safe alternative to invasive testing for confirmation of PGT-M cases that result in an ongoing pregnancy.

Experience of chromosomal microarray applied in prenatal and postnatal settings in Hong Kong.

Chromosomal microarray (CMA) is recommended as a first tier investigation for patients with developmental delay (DD), intellectual disability (ID), autistic spectrum disorder (ASD), and multiple congenital anomalies (MCA). It is widely used in the prenatal and postnatal settings for detection of chromosomal aberrations. This is a retrospective review of all array comparative genomic hybridization (aCGH/ array CGH) findings ascertained in two major prenatal and postnatal genetic diagnostic centers in Hong Kong from June 2012 to December 2017. Medical records were reviewed for cases with pathogenic and variants of uncertain clinical significance (VUS). Classification of copy number variants (CNVs) was based on current knowledge and experience by August 2018. The aims of this review are to study the diagnostic yield of array CGH application in prenatal and postnatal settings in Hong Kong and to describe the spectrum of abnormalities found. Prenatal indications included abnormal ultrasound findings, positive Down syndrome screening, abnormal noninvasive prenatal test results, advanced maternal age and family history of chromosomal or genetic abnormalities. Postnatal indications included unexplained DD, ID, ASD, and MCA. A total of 1,261 prenatal subjects and 3,096 postnatal patients were reviewed. The prenatal diagnostic yield of pathogenic CNV and VUS (excluding those detectable by karyotype) was 3.5%. The postnatal diagnostic yield of pathogenic CNV was 15.2%. The detection rates for well-defined microdeletion and microduplication syndromes were 4.6% in prenatal and 6.1% (1 in 16 index patients) in postnatal cases, respectively. Chromosomes 15, 16, and 22 accounted for over 21 and 25% of pathogenic CNVs detected in prenatal and postnatal cohorts, respectively. This review provides the first large scale overview of genomic imbalance of mostly Chinese patients in prenatal and postnatal settings.

Classification of factors involved in nonreportable results of noninvasive prenatal testing (NIPT) and prediction of success rate of second NIPT.

To evaluate the reasons for nonreportable cell-free DNA (cfDNA) results in noninvasive prenatal testing (NIPT), we retrospectively studied maternal characteristics and other details associated with the results. A multicenter retrospective cohort study in pregnant women undergoing NIPT by massively parallel sequencing (MPS) with failed cfDNA tests was performed between April 2013 and March 2017. The women's data and MPS results were analyzed in terms of maternal characteristics, test performance, fetal fraction (FF), z scores, anticoagulation therapy, and other details of the nonreportable cases. Overall, 110 (0.32%) of 34626 pregnant women had nonreportable cfDNA test results after an initial blood sampling; 22 (20.0%) cases had a low FF (<4%), and 18 (16.4%) cases including those with a maternal malignancy, were found to have altered genomic profile. Approximately half of the cases with nonreportable results had borderline z score. Among the women with nonreportable results because of altered genomic profile, the success rate of retesting using a second blood sampling was relatively low (25.0%-33.3%). Thirteen (11.8%) of the women with nonreportable results had required hypodermic heparin injection. The classification of nonreportable results using cfDNA analysis is important to provide women with precise information and to reduce anxiety during pregnancy.

Clinical Validation of Non-Invasive Prenatal Testing for Fetal Common Aneuploidies in 1,055 Korean Pregnant Women: a Single Center Experience.

BackgroundNon-invasive prenatal testing (NIPT) using cell-free fetal DNA from maternal plasma for fetal aneuploidy identification is expanding worldwide. The objective of this study was to evaluate the clinical utility of NIPT for the detection of trisomies 21, 18, and 13 of high-risk fetus in a large Korean population.MethodsThis study was performed retrospectively, using stored maternal plasma from 1,055 pregnant women with singleton pregnancies who underwent invasive prenatal diagnosis because of a high-risk indication for chromosomal abnormalities. The NIPT results were confirmed by karyotype analysis.ResultsAmong 1,055 cases, 108 cases of fetal aneuploidy, including trisomy 21 (n = 57), trisomy 18 (n = 42), and trisomy 13 (n = 9), were identified by NIPT. In this study, NIPT showed 100% sensitivity and 99.9% specificity for trisomy 21, and 92.9% sensitivity and 100% specificity for trisomy 18, and 100% sensitivity and 99.9% specificity for trisomy 13. The overall positive predictive value (PPV) was 98.1%. PPVs for trisomies 21, 18, and 13 ranged from 90.0% to 100%.ConclusionThis study demonstrates that our NIPT technology is reliable and accurate when applied to maternal DNA samples collected from pregnant women. Further large prospective studies are needed to adequately assess the performance of NIPT.

EXPERIENCE OF NON-INVASIVE PRENATAL TEST (NIPT) AT FERNANDEZ HOSPITAL.

AIM: Non -Invasive Prenatal Test is the testing for cell free fetal DNA from maternal blood during pregnancy for Trisomy 21, 18,13 and Monosomy 45XO. The aim of our study is to review our institution’s experience in the use of non-invasive prenatal test for aneuploidy screening METHODS: It is a retrospective study of pregnant women who had undergone non-invasive prenatal test between January 2015 and December 2018 at Fernandez Hospital. A detailed Ultrasonogram is done as a mandatory prerequisite before NIPT to rule out major structural anomalies; pre and post- test counselling was done to all pregnant women who underwent non-invasive prenatal test RESULTS: 322 women who had undergone non-invasive prenatal test were included in the study. 32% of the study population were of advanced maternal age. Low fetal fraction was seen in 2.1% of the study population. An abnormal non -invasive prenatal result (aneuploidy detected or inconclusive result) was reported in 36/322(11%).NIPT had a sensitivity of 100% and specificity of 99.6% in our study. Ever since NIPT has been introduced in our clinical practice the rate of invasive tests performed declined and the number of non-invasive prenatal test performed increased yearly CONCLUSION: NIPT is an excellent method for screening for aneuploidy. There is an increasing uptake of NIPT and a decline in the rate of invasive tests performed. The occurrence of false positive results emphasizes that NIPT is a screening test and not to be considered as a replacement for diagnostic tests.

Bioinformatics Pipeline for Accurate Quantification of Fetal DNA Fraction in Maternal Plasma.

The discovery of circulating cell-free fetal DNA has profoundly transformed the landscape of noninvasive prenatal testing (NIPT) and rapidly found its way into global clinical applications. The fractional concentration of cell-free fetal DNA in plasma DNA of a pregnant woman is an important parameter for understanding and interpreting analytical results of NIPT. Thus, the accurate quantification of fetal DNA fraction is indispensable when NIPT is involved. In this protocol, we describe the bioinformatics workflow to calculate fetal DNA fraction using two programs developed by our group, which provide accurate estimation.

A discordant case in which T21 positive and 47,XXYnegative non-invasive prenatal testing result wasassociated with a 47,XXY mosaic fetus

The authors report a discordant case in which T21 positive and 47,XXY negative non-invasive prenatal testing (NIPT) result was associated with a 47,XXY mosaic fetus confirmed by karyotyping. By investigating the genetic cause, the initial evidence for T21 was demonstrated to be induced by the confined placental mosaicism; the initial lack of evidence for 47,XXY could be attributed to the relatively low effective fetal fraction. This case supported that confined placental mosaicism and low effective fetal fraction are major biological risk factors associated with discordant NIPT results, and provided an unusual case for pre- and post-test NIPT counseling.

Copy number variation profile in noninvasive prenatal testing (NIPT) can identify co-existing maternal malignancies: Case reports and a literature review

ObjectiveThe coexistence of maternal malignancy and pregnancy has received increasing attention in Noninvasive prenatal testing (NIPT) studies. Malignancy in pregnant women potentially affects the copy number variation (CNV) profile in NIPT results. Only one case of hematologic cancer has been reported in a Hong-Kong pregnant women, and solid tumors have never been reported in pregnant Chinese women. Case reportThe patients with dysgerminoma and cervical cancer showed aberrant chromosomal aneuploidies in NIPT and concordant patterns of genome disruption in tumor tissues. The genomic aberrations in the gastric cancer patient had similar copy number variation pattern of gastric cancer. ConclusionThe findings in this study and the literature review further validate the effect of maternal malignancy on the copy number variation profile in NIPT data and strengthen the possibility of detecting malignant tumors with NIPT in the future.

Non-invasive prenatal screening for fetal aneuploidy in twin pregnancies by cell-free DNA analysis

Objective: To evaluate the efficacy of Cell-free DNA (cfDNA) based non-invasive prenatal testing (NIPS) in detecting fetal chromosomal aneuploidies among twin pregnancies. Materials and Methods:&nbsp;A cohort of 384 women with twin pregnancies were recruited for chromosomal aneuploidies testing through NIPS. cfDNA was extracted from maternal blood serum and sequenced by massively parallel sequencing (MPS). Result: Two cases of trisomy 21 (T21), one case of trisomy 13 (T13), and two cases of sex chromosomal aneuploidies (SCA) in twin pregnancies were correctly identified through MPS and confirmed their discordant fetal karyotypes (one normal and the other trisomy) by karyotyping; 378 twin pregnancies cases with negative NIPS results were confirmed through postnatal phone follow-up. NIPS detection rate and positive predictive value for T21, T13, and SCA were 100%, respectively, in twin pregnancies; sensitivity and specificity towards T21 and T13 in twin pregnancies were both 100%. Conclusion: cfDNA based NIPS for fetal chromosomal aneuploidy have shown a satisfactory clinical performance in twin pregnancies.

Noninvasive prenatal HPA‐1 typing in HPA‐1a negative pregnancies selected in the Polish PREVFNAIT screening program

Anti-HPA-1a alloantibodies in HPA-1a negative mothers can lead to fetal/neonatal alloimmune thrombocytopenia (FNAIT). Noninvasive prenatal testing (NIPT) of HPA-1a determines fetuses at risk and the course of maternal antenatal treatment. The aim was to develop and validate HPA-1a NIPT by real-time polymerase chain reaction (PCR) or next-generation sequencing (NGS) for a high-throughput screening setting. DNA from 328 plasma samples of 299 HPA-1a negative pregnant women was examined for HPA-1a by real-time PCR and in two cases also by NGS (Ion Torrent). The results were compared with neonatal HPA-1a genotyping in 281 cases. HPA-1a NIPT was negative in 44 of 51 HPA-1a negative fetuses, inconclusive in five, and false positive in two. In 228 of 229 HPA-1a positive fetuses, the NIPT results were positive (mean threshold cycle 36.0 ± 1.7) and inconclusive in one. In 22 cases with HPA-1a positive fetuses analyzed twice, the sensitivity of HPA-1a detection was significantly higher at 28 weeks compared with 16 to 20 weeks. NGS efficiently detected the ITGB3 coding HPA-1a/b (1% and 5% fetal HPA-1a reads). Real-time PCR is reliable to predict the fetal HPA-1a positive genotype in a screening study, but false-positive results are reported in 4%, with unnecessary prenatal treatment if anti-HPA-1a is detected.

Health economic evaluation of five prenatal screening strategies for Down's syndrome

Objective To investigate the cost-effectiveness and cost-benefit of five screening strategies for Down syndrome (DS) to optimize prenatal screening strategy. Methods A retrospective analysis was conducted in 26 803 gravidas, who underwent the second trimester maternal serum screening ( maternal serum α-fetoprotein and β-human chorionic gonadotropin) from 2002 to 2003, whom were classified into three groups according to the results of serum DS screening: high risk group (≥1/270), borderline risk group (≥1/1 000-<1/270) and elderly gravida group (age at expected date of confinement≥35 years old). TreeAge Pro 2011 sofware was used to set up the decision tree model for cost-effectiveness and cost-benefit analysis. Strategy 1: Maternal serum screening was carried out on all gravidas, and then prenatal diagnosis was performed for women in high risk group. Strategy 2: Non-invasive prenatal testing (NIPT) was carried out on all gravidas, and then prenatal diagnosis was offered for women with positive or suspected results. Strategy 3: NIPT was only carried out on gravidas of advanced maternal age and maternal serum screening was performed on the rest population. Gravidas with positive or suspected positive results in NIPT or classified into the high risk group underwent prenatal diagnosis. Strategy 4: Maternal serum screening was carried out on all gravidas. Those at high risk received prenatal diagnosis, while those at borderline risk underwent NIPT first and followed by prenatal diagnosis if positive or suspected positive NIPT results were identified. Strategy 5: Maternal serum screening was carried out on all gravidas. Those at high or borderline risk would undergo NIPT followed by prenatal diagnosis if they were positive or suspected positive for NIPT. Results (1) Among 26 803 gravidas, 1 244 were at high risk group (4.64%) with five having trisomy 21; 3 925 were at bordelrine risk (14.64%) with four having trisomy 21; 300 women were of advanced age (1.12%) with one having trisomy 21. (2) Cost-effectiveness analysis: the incremental cost-effectiveness ratios of strategy 3 and 4 were negative and that of strategy 1 was 0 with a cost-effectiveness ratio of 15 833 764.53. The incremental cost-effectiveness ratio of strategy 2 was 49 865 746.10, which was far greater than that of strategy 5 (63 049.56). The cost-effectiveness ratio of strategy 4 is 586 703.63, which was less than those of strategy 1,2 and 3 but higher than that of strategy 5. The average cost-effectiveness ratio of strategy 5 was the lowest (508 431.20) among these five strategies, which meant that for every diagnosis of DS, strategy 5 had the lowest cost (508 400 yuan). (3) Cost-benefit analysis: The benefits of strategy 4 and 5 were greater than their costs. Strategy 5 had the highest benefit-cost ratio, followed by strategy 4, 2, 3 and 1. (4) When other factors remained unchanged and only the acceptance rate of prenatal diagnosis was adjusted from 50% to 100%, strategy 1 had the least cost expectation, followed by strategy 3, 5, 4 and 2. When the cost of NIPT was below 82.4 yuan, the cost expectation of strategy 2 that performed on all gravidas was the lowest, while when it was between 82.4 and 1 827.2 yuan, the screening cost of strategy 5 was the lowest. Conclusions Strategy 5 has the best cost-effectiveness and cost-benefit. It would be the best screening strategy for DS, if the cost of NIPT is between 82.4-1 827.2 yuan. Key words: Down syndrome; Neonatal screening; Prenatal diagnosis; Costs and cost analysis; Cost-benefit analysis; High-throughput nucleotide sequencing

Results of noninvasive prenatal RHD testing in Gestation Week 25 are not affected by maternal body mass index.

Reliability of noninvasive prenatal RHD genotype test (NIP RHD) depends on having sufficient amounts of cell-free fetal DNA (cffDNA) in the maternal plasma sample. The fraction of cffDNA in maternal plasma is inversely related to maternal body mass index (BMI), suggesting that high maternal BMI may limit the test's accuracy. This study determined the effect of maternal BMI on the accuracy of NIP RHD. Results from NIP RHD performed in Gestation Week 25 were correlated to maternal BMI in Week 12. The accuracy of NIP RHD result was determined by correlation with serologic RhD types of the neonates. A total of 1618 pregnancies in 1588 D- women were included. Median BMI in these pregnancies was 24.2 (10%-90%, 20.1-32.4), and in 261 of 1618 (16%) pregnancies BMI was 30 or more (median BMI in this group was 33.6; 10th-90th percentiles, 30.5-41.1). NIP RHD was positive in 987 of 1618 (61%), negative in 582 of 1618 (36%), and inconclusive in 49 of 1618 (3.0%). Compared to the neonate's serologic RhD type, nine of 987 (0.9%) positive NIP RHD results were false positive, and four of 582 (0.7%) negative NIP RHD results were false negative (FN). In five of 49 (10%) inconclusive NIP RHD results, the neonatal RhD type was positive. There was no difference in median BMI between individuals who tested inconclusive or FN compared to those with true positive or true negative results (p = 0.80). The accuracy of NIP RHD testing performed in Gestation Week 25 does not depend on maternal BMI in the 12th gestation week.

Clinical experience with sex chromosome aneuploidies detected by noninvasive prenatal testing (NIPT): Accuracy and patient decision-making.

The objectives of the study are to assess the accuracy of noninvasive prenatal testing (NIPT) for sex chromosome aneuploidies (SCAs) and to investigate patient decision-making in clinical practice. This is a retrospective cohort study review of positive NIPT results for SCAs from January 2013 to September 2017. Of the 136 positive NIPT results for SCAs, 73 (53.7%) were positive for 45,X, 62 (45.6%) were a sex chromosome trisomy, and 1 was a sex chromosome tetrasomy. Of the 134 viable pregnancies, 46 (34.3%) elected to pursue prenatal diagnosis. Fewer women underwent invasive prenatal testing when counseled regarding a positive NIPT for monosomy X in the presence of suggestive ultrasound findings (4/23; 17.4%) compared with those who had a positive NIPT result without ultrasound findings (24/46, 52.2%). Abnormal karyotypes consistent with the NIPT result were confirmed in 30/64 (46.9%). Even in the context of ultrasound abnormalities, there was not 100% concordance. The majority (88/134; 65.7%) of patients in our cohort declined prenatal diagnosis even in the presence of associated ultrasound findings. Comprehensive pretest and posttest counseling is recommended and should address the importance of confirmatory testing and benefits of early diagnosis. Practice guidelines are needed to address provider responsibilities about postnatal testing.

The Combining Effects of Cell-Free Circulating Tumor DNA of Breast Tumor to the Noninvasive Prenatal Testing Results: A Simulating Investigation.

Massively parallel sequencing of circulating fetal DNA in the plasma of pregnant women is a common method for noninvasive prenatal testing (NIPT) of fetal trisomy 13, 18, and 21. However, circulating DNA is not restricted to pregnant women, with increased levels of plasma DNA also frequently detected in the plasma of cancer patients. Among pregnant women whose NIPT results were inconsistent with the fetal karyotype, a small number of patients have subsequently been diagnosed with a previously undetected malignancy. However, the extent to which circulating tumor DNA (ctDNA) affects the results of NIPT is still unclear. We examined serum from 50 nonpregnant women with breast tumors by NIPT. These samples were then added to serum containing trisomy 13, 18, and 21 fetal DNA to figure out the extent to which maternal tumors can interrupt NIPT results in pregnant women with breast tumors. Concentrations of cell-free DNA (cfDNA) were higher in both pregnant women and breast tumor patients, relative to nonpregnant healthy controls. Among the 50 samples evaluated, 3 produced false positive NIPT results for trisomy 13, 18, or 21, indicating that genomic copy number variations (CNVs) had occurred. Simulation testing also showed that ctDNA can increase the standard deviation of the associated z-scores, which lower absolute z-scores by decreasing the proportion of circulating fetal DNA relative to total DNA. Of the 50 samples tested, 9 fell within the equivocal range and 8 produced false negative results for trisomy 13, 18, or 21. Data presented here show for the first time that ctDNA is able to affect NIPT results in two ways. First, ctDNA can lead to false positive results due to the detection of genomic CNVs in tumor DNA. Alternatively, ctDNA can increase the likelihood of a false negative by decreasing the proportion of circulating fetal DNA in serum.

Non-invasive Prenatal Testing: A Unique Approach with Single Nucleotide Polymorphism

AbstractThe purpose of this review is to demonstrate the unique properties of a single nucleotide polymorphism (SNP)-based approach in non-invasive prenatal testing (NIPT). The identification of cell free fetal DNA in the plasma of pregnant women led to the development of NIPT. This can be performed with either a quantitative approach (massively parallel shotgun sequencing, chromosome selective sequencing) or a qualitative approach (SNP-based). NIPT tests have been shown to have superior performance as a screen for common fetal chromosome abnormalities compared with maternal serum screening. At low fetal fractions, NIPT sensitivity falls, particularly when quantitative methods are used. A SNP-based approach allows both accurate assessment of fetal fraction, and a robust test performance at lower fetal fractions. The ability of the SNP-based approach to screen for vanishing twins and maternal copy number variants reduces false positives; and the ability to make high confidence calls at lower fetal fraction, minimizes discordance between the NIPT result and the true fetal status.

Has Noninvasive Prenatal Testing Impacted Termination of Pregnancy and Live Birth Rates of Infants With Down Syndrome?

Background Implementation of noninvasive prenatal testing (NIPT) as a highly accurate aneuploidy screening test has raised questions around whether the high uptake may result in more terminations of pregnancies and fewer births of children with Down syndrome (DS). Aim The aim of the study was to investigate the impact of NIPT on termination and live birth rates for DS. Methods Literature reporting pregnancy outcomes following NIPT was reviewed. Termination rates were calculated for women with a high-risk NIPT result for DS. Two audits of pregnancy outcomes where NIPT indicated DS were conducted in the United Kingdom and Singapore. Results Fourteen studies from the United States, Asia, Europe, and the United Kingdom were included in the review. Live births of children with DS were reported in 8 studies. Termination rates following NIPT were unchanged or decreased when compared to termination rates prior to the introduction of NIPT. Audits found 15 of 43 women in the United Kingdom and 2 of 6 in Singapore continued pregnancies following a high-risk NIPT result. Conclusions Termination rates following the detection of DS by NIPT are unchanged or decreased compared to historical termination rates. Impact on live birth rates may be minimal in settings where termination rates fall. Population-based studies are required to determine the true impact.