Systematic evaluation of NIPT aneuploidy detection software tools with clinically validated NIPT samples

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

BACKGROUND

NIPT is becoming increasingly important as its use becomes more widespread in China. More details are urgently needed on the correlation between maternal risk factors and fetal aneuploidy, and how these factors affect the accuracy of prenatal aneuploidy screening.

METHODS

Information on the pregnant women was collected, including maternal age, gestational age, specific medical history and results of prenatal aneuploidy screening. Additionally, the OR, validity and predictive value were also calculated.

RESULTS

A total of 12,186 analysable karyotype reports were collected with 372 (3.05%) fetal aneuploidies, including 161 (1.32%) T21, 81 (0.66%) T18, 41 (0.34%) T13 and 89 (0.73%) SCAs. The OR was highest for maternal age less than 20 years (6.65), followed by over 40 years (3.59) and 35-39 years (2.48). T13 (16.95) and T18 (9.40) were more frequent in the over-40 group (P < 0.01); T13 (3.62/5.76) and SCAs (2.49/3.95) in the 35-39 group (P < 0.01). Cases with a history of fetal malformation had the highest OR (35.94), followed by RSA (13.08): the former was more likely to have T13 (50.65) (P < 0.01) and the latter more likely to have T18 (20.50) (P < 0.01). The sensitivity of primary screening was 73.24% and the NPV was 98.23%. The TPR for NIPT was 100.00% and the respective PPVs for T21, T18, T13 and SCAs were 89.92, 69.77, 53.49 and 43.24%, respectively. The accuracy of NIPT increased with increasing gestational age (0.81). In contrast, the accuracy of NIPT decreased with maternal age (1.12) and IVF-ET history (4.15).

CONCLUSIONS

①Pregnant patients with maternal age below 20 years had higher risk of aneuploidy, especially in T13; ②A history of fetal malformations is more risky than RSA, with the former more likely to have T13 and the latter more likely to have T18; ③Primary screening essentially achieves the goal of identifying a normal karyotype, and NIPT can accurately screen for fetal aneuploidy; ④A number of maternal risk factors may influence the accuracy of NIPT diagnosis, including older age, premature testing, or a history of IVF-ET. In conclusion, this study provides a reliable theoretical basis for optimizing prenatal aneuploidy screening strategies and improving population quality.

False-positives and false-negatives in non-invasive prenatal testing (NIPT): what can we learn from a meta-analyses on > 750,000 tests?

Background

Non-invasive prenatal testing (NIPT) has had an incomparable triumph in prenatal diagnostics in the last decade. Over 1400 research articles have been published, predominantly praising the advantages of this test.

Methods

The present study identified among the 1400 papers 24 original and one review paper, which were suited to re-evaluate the efficacy of > 750,000 published NIPT-results. Special attention was given to false-positive and false-negative result-rates. Those were discussed under different aspects—mainly from a patient-perspective.

Results

A 27: 1 rate of false-positive compared to false-negative NIPT results was found. Besides, according to all reported, real-positive, chromosomally aberrant NIPT cases, 90% of those would have been aborted spontaneously before birth. These findings are here discussed under aspects like (i) How efficient is NIPT compared to first trimester screening? (ii) What are the differences in expectations towards NIPT from specialists and the public? and (iii) There should also be children born suffering from not by NIPT tested chromosomal aberrations; why are those never reported in all available NIPT studies?

Conclusions

Even though much research has been published on NIPT, unbiased figures concerning NIPT and first trimester screening efficacy are yet not available. While false positive rates of different NIPT tests maybe halfway accurate, reported false-negative rates are most likely too low. The latter is as NIPT-cases with negative results for tested conditions are yet not in detail followed up for cases with other genetic or teratogenic caused disorders. This promotes an image in public, that NIPT is suited to replace all invasive tests, and also to solve the problem of inborn errors in humans, if not now then in near future. Overall, it is worth discussing the usefulness of NIPT in practical clinical application. Particularly, asking for unbiased figures concerning the efficacy of first trimester-screening compared to NIPT, and for really comprehensive data on false-positive and false-negative NIPT results.

Assessment of Maternal Serum Biochemical Attributes and Fetal Ultrasound Scans in First-Trimester Low-Risk Noninvasive Prenatal-Tested Pregnant Women

INTRODUCTION

The first trimester of pregnancy is marked by several important disrupting changes as a result of complex biological upshot of events required for the development of the fetus. These changes in the biological events result in changes in the maternal serum biomarkers that are associated with fetal growth. The aim of the present study was to evaluate the correlation between the maternal blood biochemical determinants such as pregnancy-associated plasma protein-A (PAPP-A) and alpha fetoprotein (AFP) with ultrasound scans during early pregnancy in the first trimester.

METHODS

The study included 139 women whose fetus was alive between 11±1 weeks of gestation. The risk of fetal chromosomal abnormalities at first trimester was analyzed by the VeriSeq NIPT Solution v2 platform (Illumina, San Diego, CA, USA) for noninvasive prenatal testing (NIPT) assay. The PAPP-A and AFP levels were evaluated by chemiluminescent immunoassays. The levels of PAPP-A and AFP were correlated with the fetal heart rate (HR), crown rump length (CRL), and nuchal translucency (NT) by Pearson's correlation analysis.

RESULTS

The mean age of the participants was 28.35±3.87 years (minimum=21, maximum=35). The mean AFP and PAPP-A levels in the maternal plasma were 14.76±1.04 ng/mL and 4.37±0.86 mIU/ml respectively. The mean FHR, CRL, and NT were 138±7.62 bpm, 59±3.24 mm, and 2.3±0.61 mm respectively. PAPP-A and AFP significantly (p<0.05) correlated with fetal HR, CRL, and NT at 11±1 weeks of gestation. The mean ratio of AFP:PAPP-A in low-risk pregnancies was 3.37.

CONCLUSIONS

The maternal serum biochemical attributes correlated well with the fetal ultrasound scans. The findings of the present study can prove to be clinically useful for clinical research, obstetrics, and gynaecology, especially for examinations of first-trimester pregnancies.