A cross-country comparison of pregnant women's decision-making and perspectives when opting for non-invasive prenatal testing in the Netherlands and Belgium

Background

The Netherlands and Belgium have been among the first countries to offer non-invasive prenatal testing (NIPT) as a first-tier screening test. Despite similarities, differences exist in counseling modalities and test uptake. This study explored decision-making and perspectives of pregnant women who opted for NIPT in both countries.

Methods

A questionnaire study was performed among pregnant women in the Netherlands (NL) (n = 587) and Belgium (BE) (n = 444) opting for NIPT, including measures on informed choice, personal and societal perspectives on trisomy 21, 18 and 13 and pregnancy termination.

Results

Differences between Dutch and Belgian women were shown in the level of informed choice (NL: 83% vs. BE: 59%, p < 0.001), intention to terminate the pregnancy in case of confirmed trisomy 21 (NL: 51% vs. BE: 62%, p = 0.003) and trisomy 13/18 (NL: 80% vs. BE: 73%, p = 0.020). More Belgian women considered trisomy 21 a severe condition (NL: 64% vs. BE: 81%, p < 0.001). Belgian women more frequently indicated that they believed parents are judged for having a child with trisomy 21 (BE: 42% vs. NL: 16%, p < 0.001) and were less positive about quality of care and support for children with trisomy 21 (BE: 23% vs. NL: 62%, p < 0.001).

Conclusion

Differences in women's decision-making regarding NIPT and the conditions screened for may be influenced by counseling aspects and country-specific societal and cultural contexts.     

Ethical issues associated with prenatal screening using non-invasive prenatal testing for sex chromosome aneuploidy

Prenatal screening for sex chromosome aneuploidies (SCAs) is increasingly available through expanded non-invasive prenatal testing (NIPT). NIPT for SCAs raises complex ethical issues for clinical providers, prospective parents and future children. This paper discusses the ethical issues that arise around NIPT for SCAs and current guidelines and protocols for management. The first section outlines current practice and the limitations of NIPT for SCAs. It then outlines key guidelines before discussing the ethical issues raised by this use of NIPT. We conclude that while screening for SCAs should be made available for people seeking to use NIPT, its implementation requires careful consideration of what, when and how information is provided to users.     

Discordant results between fetal karyotyping and non-invasive prenatal testing by maternal plasma sequencing in a case of uniparental disomy 21 due to trisomic rescue

Uniparental disomy (UPD) is an uncommon chromosome condition, but UPD involving chromosome 21 is rarely reported. We reported here a case who had first trimester screening test for Down syndrome, chorionic villus sampling for fetal karyotyping, quantitative fluorescence polymerase chain reaction (QF-PCR), as well as non-invasive prenatal testing (NIPT) by maternal plasma sequencing. There were discordant results between fetal karyotyping and NIPT due to UPD 21combined with confined placental mosaicism of trisomy 21. This demonstrated that it is possible to detect placental mosaicism by NIPT, but further studies are required to confirm its sensitivity. Therefore, all positive NIPT results must be confirmed by conventional invasive test and karyotyping. QF-PCR has the additional benefit in diagnosing UPD. © 2013 John Wiley & Sons, Ltd.     

Do recent US Supreme Court rulings on patenting of genes and genetic diagnostics affect the practice of genetic screening and diagnosis in prenatal and reproductive care?

Thousands of patents have been awarded that claim human gene sequences and their uses, and some have been challenged in court. In a recent high-profile case, Association for Molecular Pathology, et al. v. Myriad Genetics, Inc., et al., the US Supreme Court ruled that genes are natural occurring substances and therefore not patentable through ‘composition of matter’ claims. The consequences of this ruling will extend well beyond ending Myriad's monopoly over BRCA testing and may affect similar monopolies of other commercial laboratories for tests involving other genes. It could also simplify intellectual property issues surrounding genome-wide clinical sequencing, which can generate results for genes covered by intellectual property. Non-invasive prenatal testing (NIPT) for common aneuploidies using cell-free fetal (cff) DNA in maternal blood is currently offered through commercial laboratories and is also the subject of ongoing patent litigation. The recent Supreme Court decision in the Myriad case has already been invoked by a lower district court in NIPT litigation and resulted in invalidation of primary claims in a patent on currently marketed cffDNA-based testing for chromosomal aneuploidies. © 2014 John Wiley & Sons, Ltd.     

Overview of the impact of noninvasive prenatal testing on diagnostic procedures

Noninvasive prenatal testing (NIPT) has had a profound influence in the field of prenatal diagnosis since the 1997 discovery of cell-free fetal DNA in maternal blood. Research has progressed rapidly, with clinical data supporting laboratory studies showing that NIPT is highly sensitive and specific for fetal aneuploidy, resulting in marked uptake in the high-risk patient population. The superior accuracy of NIPT compared with conventional screening methods has led to significant decreases in the number of invasive diagnostic procedures, in addition to a concomitant decrease in the number of procedure-related fetal losses. Yet, NIPT has been described as a ‘disruptive innovation’ due to the considerable changes the technology has commanded on current prenatal screening and diagnostic practices. This review summarizes both institutional and global experience with NIPT uptake, its effect on reducing diagnostic invasive procedures, and the unique challenges that reduced procedural volume may have on physician and trainee proficiency, cytogenetic laboratories, and neonatal outcome. © 2015 John Wiley & Sons, Ltd.     

The impact of non-invasive prenatal testing on anxiety in women considered at high or low risk for aneuploidy after combined first trimester screening

Objective: The aim of this study was to (1) examine the psychological impact of non-invasive prenatal testing (NIPT) in women with a high-risk (≥1 : 300) and low-risk (≤1 : 301) result on combined first trimester screening (cFTS) and (2) to examine factors influencing anxiety and decision-making in both risk populations. Method: Questionnaires and structured interviews were administered to low (n = 50) and high (n = 63) risk women at the time of NIPT blood draw (point A) and again at least 1 week after receiving their NIPT result (point B). Anxiety levels were measured at these two time points using the State–Trait Anxiety Inventory. Results: Both high-risk and low-risk cFTS groups demonstrated similar intrinsic (trait) anxiety levels (36 ± 10 vs 35 ± 10; p = 0.70). High-risk women had significantly higher levels of state anxiety at point A than low-risk women (42 ± 11 vs 36 ± 11; p < 0.01). Both groups had a statistically significant reduction (p < 0.01), to similar final levels of state anxiety at point B (30 ± 11 vs 29 ± 8; p = 0.61). Conclusion: Women receiving a high-risk result on cFTS have higher levels of state anxiety than their low-risk counterparts. Following a low-risk NIPT result, the anxiety levels in both populations are reduced to similar levels. © 2017 John Wiley & Sons, Ltd.     

Non-invasive prenatal testing in the management of twin pregnancies

Twin pregnancies are common and associated with pregnancy complications and adverse outcomes. Prenatal clinical management is intensive and has been hampered by inferior screening and less acceptable invasive testing. For aneuploidy screening, meta-analyses show that non-invasive prenatal testing (NIPT) through analysis of cell-free DNA (cf-DNA) is superior to serum and ultrasound-based tests. The positive predictive value for NIPT is driven strongly by the discriminatory power of the assay and only secondarily by the prior risk. Uncertainties in a priori risks for aneuploidies in twin pregnancies are therefore of lesser importance with NIPT. Additional information on zygosity can be obtained using NIPT. Establishing zygosity can be helpful when chorionicity was not reliably established early in pregnancy or where the there is a concern for one versus two affected fetuses. In dizygotic twin pregnancies, individual fetal fractions can be measured to ensure that both values are satisfactory. Vanishing twins can be identified by NIPT. Although clinical utility of routinely detecting vanishing twins has not yet been demonstrated, there are individual cases where cf-DNA analysis could be helpful in explaining unusual clinical or laboratory observations. We conclude that cf-DNA analysis and ultrasound have synergistic roles in the management of multiple gestational pregnancies.     

Recommended pre-test counseling points for noninvasive prenatal testing using cell-free DNA: a 2015 perspective

Noninvasive prenatal testing (NIPT) using cell-free DNA is being offered to an increasing number of women. Comprehensive pre-test counseling is complicated by emerging information about the benefits and limitations of testing, as well as the potential to detect incidental findings. Genetic counselors are trained to facilitate informed decision-making; however, not all centers have access to these professionals. To aid in the informed consent process, we have summarized key points to be included in discussions with patients who are considering NIPT. © 2015 John Wiley & Sons, Ltd.     

State-wide increase in prenatal diagnosis of klinefelter syndrome on amniocentesis and chorionic villus sampling: Impact of non-invasive prenatal testing for sex chromosome conditions

Background

To analyze population-based trends in the prenatal diagnosis of sex chromosome aneuploidy (SCA) since the availability of non-invasive prenatal testing (NIPT).

Methods

Retrospective state-wide data for all prenatal diagnoses performed <25 weeks gestation from 2005 to 2020 in Victoria, Australia. Non-invasive prenatal testing became locally available from 2012. The prenatal diagnosis rates of SCA as proportions of all prenatal diagnostic tests and all births were calculated. Statistical significance was assessed with the χ² test for trend, with p < 0.05 considered significant.

Results

46,518 amniocentesis and chorionic villus sampling were performed during the study period, detecting 617 SCAs. There was a significant increase in the rate of prenatal SCAs from 5.8 per 10,000 births in 2005 to 8.7 per 10,000 births in 2020 (p < 0.0001). This increase was predominantly due to 47,XXY cases, 91% of which were ascertained via positive NIPT for this condition in 2020. The prenatal diagnosis rate of 47,XXY significantly increased from 0.8 per 10,000 births in 2005 to 4.3 per 10,000 births in 2020 (p < 0.0001).

Conclusion

Screening for SCAs using NIPT has directly led to an increase in their prenatal diagnosis on a population-wide basis, especially 47,XXY. This has implications for clinician education, genetic counselling, and pediatric services.     

Factors involved in the decision to decline prenatal screening with noninvasive prenatal testing (NIPT)

Objective

To investigate factors involved in the decision to decline prenatal screening with noninvasive prenatal testing (NIPT).

Method

A questionnaire study was conducted among 219 pregnant women in the Netherlands who had declined prenatal screening with NIPT (TRIDENT-2 study). Respondents were selectively recruited from three hospitals and 19 midwifery practices, primarily located in or near socioeconomically disadvantaged neighborhoods. 44.3% of the respondents were of non-Western ethnic origin and 64.4% were religious.

Results

Most respondents (77.2%) found the decision to decline NIPT easy to make, and 59.8% had already made the decision before information about NIPT was offered. These respondents were more often religious, multigravida, and had adequate health literacy. The main reasons to decline NIPT were “I would never terminate my pregnancy” (57.1%) and “every child is welcome” (56.2%). For 16.9% of respondents, the out-of-pocket costs (175 euros) played a role in the decision, and the women in this group were more often nonreligious, primigravida, and had inadequate health literacy.

Conclusion

The primary factors involved in the decision to decline NIPT were related to personal values and beliefs, consistent with autonomous choice. Out-of-pocket costs of NIPT hinder equal access for some pregnant women.     

Non-invasive prenatal testing (NIPT): Combination of copy number variant and gene analyses using an “in-house” target enrichment next generation sequencing—Solution for non-centralized NIPT laboratory?

Objective

Recent studies have integrated copy number variant (CNV) and gene analysis using target enrichment. Here, we transferred this concept to our routine genetics laboratory, which is not linked to centralized non-invasive prenatal testing (NIPT) facilities.

Method

From a cohort of 100 pregnant women, 22 were selected for the analysis of maternal genomic DNA (gDNA) along with fetal cell-free DNA. Using targeted enrichment, 135 genes were analyzed, combined with aberrations of chromosomes 21, 18, 13, X, and Y. The data were subjected to specificity and sensitivity analyses, and correlated with the results from invasive testing methods.

Results

The sensitivity/specificity was determined for the CNV analysis of chromosomes: 21 (80%/75%), 18 (-/82%), 13 (100%/67%), and Y (100%/100%). The gene detection was valid for maternal gDNA. However, for cell-free fetal DNA, it was not possible to determine the boundary between an artifact and a real sequence variant.

Conclusion

The target enrichment method combining CNV and gene detection seems feasible in a regular laboratory. However, this method can only be responsibly optimized with a sufficient number of controls and further validation on a strong bioinformatic background. The present results showed that NIPT should be performed in specialized centers, and that its introduction to isolated laboratories may not provide valid data.     

Discordant non-invasive prenatal testing (NIPT) – a systematic review

With a high sensitivity and specificity, non-invasive prenatal testing (NIPT) is an incomparable screening test for fetal aneuploidy. However, the method is rather newly introduced, and experiences with discordant results are few. We did a systematic review of literature reporting details of false positive and false negative NIPT results. Discordant sex chromosome results were not included. We identified 22 studies reporting case details. In total, 206 discordant cases were included, of which 88% were false positive and 12% false negative. Details on maternal age, gestational age, platform/company, Z-score, fetal fraction, results and explanation were specified. The main reasons for discordant results were confined placental mosaicism, maternal copy number variation, vanished twin, maternal cancer and true fetal mosaicism. A very high percentage of cases (67%) were reported with no obvious biological or technical explanation for the discordant result. The included cases represent only a minor part of the true number of false positive or false negative NIPT cases identified in fetal medicine clinics around the world. To ensure knowledge exchange and transparency of NIPT between laboratories, we suggest a systematic recording of discordant NIPT results, as well as a quality assurance by external quality control and accreditation. © 2017 John Wiley & Sons, Ltd.     

Overview and recent developments in cell-based noninvasive prenatal testing

Investigators have long been interested in the natural phenomenon of fetal and placental cell trafficking into the maternal circulation. The scarcity of these circulating cells makes their detection and isolation technically challenging. However, as a DNA source of fetal origin not mixed with maternal DNA, they have the potential of considerable benefit over circulating cell-free DNA-based noninvasive prenatal genetic testing (NIPT). Endocervical trophoblasts, which are less rare but more challenging to recover are also being investigated as an approach for cell-based NIPT. We review published studies from around the world describing both forms of cell-based NIPT and highlight the different approaches’ advantages and drawbacks. We also offer guidance for developing a sound cell-based NIPT protocol.     

Detection rates and residual risk for a postnatal diagnosis of an atypical chromosome aberration following combined first-trimester screening

Objectives

To determine the detection rates of all types of chromosome aberrations and the residual risk for postnatal diagnosis of an atypical chromosome aberration depending on the strategy for further investigation with either noninvasive prenatal testing (NIPT) or invasive testing in pregnancies with increased risk following combined first-trimester screening (cFTS).

Methods

A review of all pregnancies examined with cFTS during 2010 to 2017.

Results

The cohort consisted of 129 493 pregnancies. There were 852 (0.7%) clinically significant chromosome aberrations, including aberrations detected later on or after birth. A total of 12% were atypical chromosome aberrations. Considering that 40% were detected due to a miscarriage/intrauterine fetal death or a malformation on ultrasound there is a 0.05% (1:2000) background risk of a postnatal diagnosis of a liveborn child with an atypical chromosome aberration if no further invasive test is performed during pregnancy. If all women with an increased risk (≥1:200) had an invasive test and NIPT was performed up to a risk of 1:1000, 95% of common trisomies/sex chromosome aberrations and 55% of atypical aberrations would be detected.

Conclusions

If NIPT was offered to all women with an increased risk following cFTS it would imply that three times as many children would be born with an atypical chromosome aberration.     

Non-invasive prenatal testing (NIPT) in twin pregnancies affected by early single fetal demise: A systematic review of NIPT and vanishing twins

The screening performance of non-invasive prenatal testing (NIPT) in vanishing twin (VT) pregnancies is relatively unknown. To close this knowledge gap, we conducted a systematic review of the available literature. Studies describing the test performance of NIPT for trisomy 21, 18, 13, sex chromosomes and additional findings in pregnancies with a VT were retrieved from a literature search with a publication date until October 4, 2022. The methodological quality of the studies was assessed with the quality assessment tool for diagnostic accuracy studies-2 (QUADAS-2). The screen positive rate of the pooled data and the pooled positive predictive value (PPV) were calculated using a random effects model. Seven studies, with cohort sizes ranging from 5 to 767, were included. The screen positive rate of the pooled data for trisomy 21 was 35/1592 (2.2%), with a PPV of 20% (confirmation in 7/35 cases [95% CI 9.8%–36%]). For trisomy 18, the screen positive rate was 13/1592 (0.91%) and the pooled PPV 25% [95% CI 1.3%–90%]. The screen positive rate for trisomy 13 was 7/1592 (0.44%) and confirmed in 0/7 cases (pooled PPV 0% [95% CI 0%–100%]). The screen positive rate for additional findings was 23/767 (2.9%), of which none could be confirmed. No discordant negative results were reported. There is insufficient data to fully evaluate NIPT performance in pregnancies with a VT. However, existing studies suggest that NIPT can successfully detect common autosomal aneuploidies in pregnancies affected by a VT but with a higher false positive rate. Further studies are needed to determine the optimal timing of NIPT in VT pregnancies.     

Inclusion of sex chromosomes in noninvasive prenatal testing in Asia,Australia, Europe and the USA: A survey study

Objective

To examine the extent to which sex chromosomes are included in current noninvasive prenatal testing (NIPT) and the reporting practices with respect to fetal chromosomal sex and sex chromosome aberrations (SCAs), in addition to an update on the general implementation of NIPT.

Method

A questionnaire addressing the research objectives was distributed by email to fetal medicine and clinical genetics experts in Asia, Australia, Europe and the USA.

Results

Guidelines on NIPT are available in the majority of the included countries. Not all existing guidelines address reporting of fetal chromosomal sex and SCAs. In most settings, NIPT frequently includes sex chromosomes (five Australian states, China, Hong Kong, Israel, Singapore, Thailand, USA and 23 of 31 European countries). This occurs most often by default or when parents wish to know fetal sex. In most settings, a potential SCA is reported by stating the risk hereof as “low” or “high” and/or by naming the SCA. Less than 50% of all pregnant women receive NIPT according to respondents from three Australian states, China, Israel, Singapore, Thailand and 24 of 31 European countries. However, this percentage, the genomic coverage of NIPT and its application as primary or secondary screening vary by setting.

Conclusion

In most of the studied countries/states, NIPT commonly includes sex chromosomes. The reporting practices concerning fetal chromosomal sex and SCAs are diverse and most commonly not addressed by guidelines. In general, NIPT is variably implemented across countries/states.     

The fragmentation patterns of maternal plasma cell-free DNA and its applications in non-invasive prenatal testing

The discovery of cell-free DNA (cfDNA) in maternal plasma has opened up new promises for the development of non-invasive prenatal testing (NIPT). Application of cfDNA in NIPT of fetus diseases and abnormalities is restricted by the low amount of fetal DNA molecules in maternal plasma. Fetus-derived cfDNA in maternal plasma are shorter than maternal DNA, thus leveraging the maternal and fetus-derived cfDNA molecules size difference has become a novel and more accurate method for NIPT. However, multiple biological properties such as size distribution of plasma DNA, proportion of fetal-derived DNA and methylation levels in maternal plasma across different gestational ages still remain largely unknown. Further insights into the size distribution and fragmentation pattern of circulating plasma cfDNA will shed light on the origin and fragmentation mechanisms of cfDNA during physiological and pathological processes in prenatal diseases and enhance our ability to take the advantage of plasma cfDNA as a molecular diagnostic tool. In the review, we start by summarizing the research techniques for the determination of the fragmentation profiles of cfDNA in maternal plasma. We then summarize the main progress and findings in size profiles of maternal plasma cfDNA and cffDNA. Finally, we discuss the potential diagnostic applications of plasma cfDNA size profiling.     

Antenatal screening for fetal trisomies using microarray-based cell-free DNA testing: A systematic review and meta-analysis

Objective

To evaluate the test accuracy of non-invasive prenatal testing (NIPT) for fetal trisomy 21, 18, and 13 using cell-free (cf) DNA analysis in maternal plasma with microarray quantitation.

Method

Systematic review and meta-analysis. Searches in MEDLINE, Pre-MEDLINE, EMBASE, Web of Science, and the Cochrane Library to 09.07.2018.

Results

Five studies analyzing 3074 samples, including 187 trisomy 21, 43 trisomy 18, and 19 trisomy 13 cases, were identified. Risk of bias was high in all studies, introduced particularly by exclusions from analysis and by the role of the sponsor. Sensitivity of microarray-based cfDNA testing was 99.5% (95%CI 96.3%-99.9%) for trisomy 21, 97.7% (95%CI 87.9%-99.6%) for trisomy 18, and 100% (95%CI 83.2%-100%) for trisomy 13. Specificity was 100% (95% CI 99.87%-100%) for trisomy 21, 99.97% (95%CI 99.81%-99.99%) for trisomy 18, and 99.97% (95%CI 99.81%-99.99%) for trisomy 13. Pooled test failure rate was 1.1%. A direct comparison of microarray- and sequencing-based cfDNA found equivalent test accuracy.

Conclusion

Included studies suggest that NIPT using microarray-based cfDNA testing has high sensitivity and specificity for detecting fetal trisomy 21, 18, and 13. However, the evidence base is small and at high risk of bias.     

Benefits and limitations of prenatal screening for Prader–Willi syndrome

This review summarizes the status of genetic laboratory testing in Prader–Willi syndrome (PWS) with different genetic subtypes, most often a paternally derived 15q11–q13 deletion and discusses benefits and limitations related to prenatal screening. Medical literature was searched for prenatal screening and genetic laboratory testing methods in use or under development and discussed in relationship to PWS. Genetic testing includes six established laboratory diagnostic approaches for PWS with direct application to prenatal screening. Ultrasonographic, obstetric and cytogenetic reports were summarized in relationship to the cause of PWS and identification of specific genetic subtypes including maternal disomy 15. Advances in genetic technology were described for diagnosing PWS specifically DNA methylation and high-resolution chromosomal SNP microarrays as current tools for genetic screening and incorporating next generation DNA sequencing for noninvasive prenatal testing (NIPT) using cell-free fetal DNA. Positive experiences are reported with NIPT for detection of numerical chromosomal problems (aneuploidies) but not for structural problems (microdeletions). These reports will be discussed along with future directions for genetic screening of PWS. In summary, this review describes and discusses the status of established and ongoing genetic testing options for PWS applicable in prenatal screening including NIPT and future directions for early diagnosis in PWS. © 2016 John Wiley & Sons, Ltd.