European Journal of Cardiovascular Medicine

Non-invasive prenatal testing (NIPT) and invasive prenatal diagnostic procedures (IPDPs) are two key methodologies used in prenatal care to assess fetal genetic conditions [1]. NIPT, a relatively recent development, relies on the analysis of cell-free fetal DNA (cfDNA) present in the maternal blood to screen for conditions such as Down syndrome (trisomy 21), trisomy 18, and trisomy 13, among others. These non-invasive procedures offer the advantage of eliminating the need for amniocentesis or chorionic villus sampling (CVS), which carry inherent risks to the pregnancy, including miscarriage and fetal injury. Given the growing prominence of NIPT in clinical practice, there is an increasing need to evaluate its diagnostic performance relative to the well-established invasive procedures. This meta-analysis aims to provide an in-depth comparison of the diagnostic accuracy of NIPT versus invasive prenatal diagnostic methods in detecting common chromosomal abnormalities, with a specific focus on evaluating the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) across different studies. The development of NIPT, which leverages next-generation sequencing (NGS) technology, marked a pivotal shift in prenatal care. Unlike traditional serum-based screening tests, NIPT provides a higher level of accuracy by directly analyzing fetal DNA fragments circulating in maternal blood. As a result, NIPT has garnered considerable attention due to its enhanced sensitivity and specificity in detecting fetal aneuploidies, particularly for trisomy 21, which remains the most commonly detected chromosomal abnormality in live births [2] Several studies have demonstrated that NIPT is highly accurate, with a sensitivity for trisomy 21 approaching 99%, which outperforms conventional screening methods such as maternal serum screening and nuchal translucency ultrasound [3]. Invasive procedures, on the other hand, have long been the gold standard for prenatal diagnosis. Amniocentesis and CVS are invasive diagnostic techniques that allow for the direct analysis of fetal cells, thus providing definitive information about the presence of chromosomal abnormalities. Although these methods are highly accurate, they come with significant risks, including the potential for miscarriage, premature labor, and fetal injury. According to a study by, the miscarriage rate associated with amniocentesis is estimated to be between 0.1% and 0.3%, while the rate for CVS is slightly higher at around 0.5% [4]. Consequently, these risks have prompted an increasing number of pregnant women to seek less invasive alternatives, leading to the rapid adoption of NIPT. Given the critical nature of prenatal genetic testing in identifying fetal chromosomal abnormalities, it is essential to compare the diagnostic accuracy of NIPT and invasive procedures across a broad range of studies. The aim of this meta-analysis is to synthesize data from multiple sources to provide a robust evaluation of the performance of both methods. This analysis will focus on key metrics such as sensitivity, specificity, PPV, and NPV, which are essential for assessing the clinical utility of diagnostic tests. Furthermore, the meta-analysis will take into account various factors that may influence the diagnostic performance of NIPT and invasive procedures, such as maternal age, gestational age at testing, and the use of different testing technologies. The growing reliance on NIPT for screening has raised questions about its role as a substitute for invasive procedures, particularly in high-risk pregnancies. While NIPT has demonstrated superior performance in screening for common aneuploidies, it is important to consider the limitations of NIPT in certain clinical settings. For example, NIPT is not able to detect structural chromosomal abnormalities, such as deletions, duplications, and translocations, which can be identified through invasive procedures [5]. Additionally, NIPT's diagnostic performance can vary depending on factors such as the quality of the cfDNA sample, maternal weight, and the presence of multiple fetuses, which may lead to false-negative or false-positive results [6]. In contrast, invasive procedures offer a definitive diagnosis of chromosomal abnormalities by directly analyzing fetal cells. This makes invasive procedures particularly valuable in cases where NIPT results are inconclusive or when there is a clinical suspicion of a more complex chromosomal abnormality. However, due to the associated risks, invasive procedures are typically reserved for cases where there is a strong indication for genetic testing, such as in women over the age of 35 or those with a family history of genetic disorders.

Aims and Objective

The aim of this study is to compare the diagnostic performance of Non-Invasive Prenatal Testing (NIPT) and Invasive Prenatal Diagnostic Procedures (IPDPs) in detecting fetal chromosomal abnormalities, focusing on accuracy, sensitivity, specificity, and predictive values. The objective is to provide evidence-based recommendations for clinical decision-making in prenatal screening.

Study Design

This study is a retrospective cohort analysis conducted at Gouri Devi Institute of Medical Science, Durgapur, West Bengal, India, over one year (January 2023 to December 2024). The study involved a total of 50 cases where both Non-Invasive Prenatal Testing (NIPT) and invasive prenatal diagnostic procedures (IPDPs) were performed on pregnant women to detect fetal chromosomal abnormalities such as trisomy 21, trisomy 18, and trisomy 13. The study aimed to compare the diagnostic performance of these two methods in terms of sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Ethical approval for the study was obtained from the institutional review board (IRB), ensuring adherence to all ethical guidelines in research.

Inclusion Criteria

Pregnant women aged 18–45 years, with no prior history of fetal chromosomal abnormalities, were included in the study. All participants had undergone both NIPT and invasive diagnostic procedures (amniocentesis or CVS) for chromosomal screening. Patients with a single pregnancy, no known risk factors for aneuploidy, and those willing to participate in the study were also eligible. These participants provided informed consent to take part in the study.

Exclusion Criteria

Pregnant women with multiple pregnancies, those with a known history of fetal chromosomal abnormalities or structural birth defects, were excluded from the study. Additionally, patients with medical conditions such as gestational diabetes, hypertension, or autoimmune diseases were excluded, as these conditions could influence the accuracy of the test results. Participants who had incomplete data or failed to undergo both NIPT and invasive procedures were also excluded to maintain the integrity of the study’s results.

Data Collection

Data for this study were collected from patient records at the Gouri Devi Institute of Medical Science. The medical history, demographic information, and clinical data were extracted from the hospital database. The number of cases that underwent both NIPT and invasive diagnostic procedures for detecting trisomy 21, trisomy 18, and trisomy 13 was recorded. Diagnostic results, including sensitivity, specificity, and predictive values, were documented and analyzed. Informed consent was obtained from all participants before inclusion.

Data Analysis

The collected data were analyzed using SPSS version 26.0 (Statistical Package for the Social Sciences). Descriptive statistics were used to summarize the demographic and clinical characteristics of the study population. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for both NIPT and invasive procedures. The comparison of diagnostic performance between NIPT and invasive methods was performed using t-tests, chi-square tests, and p-value calculations. Standard deviation and confidence intervals were also determined to assess the consistency and reliability of the results.

Procedure

Upon patient enrollment, informed consent was obtained, and the required data, including demographic details and medical history, were recorded. All participants underwent both NIPT and invasive prenatal diagnostic procedures (CVS or amniocentesis) as part of their routine prenatal care. NIPT was performed by analyzing maternal plasma for cell-free fetal DNA (cfDNA) using next-generation sequencing (NGS) technology. The invasive procedures involved the collection of fetal cells from amniotic fluid (amniocentesis) or chorionic villi (CVS), which were then cultured and analyzed using karyotyping or chromosomal microarray analysis. The results from both tests were compared in terms of diagnostic performance, including sensitivity, specificity, PPV, and NPV. Statistical methods were employed to assess the accuracy and reliability of both methods, with the goal of determining which method provided more accurate results for detecting chromosomal abnormalities. The study also considered various factors that might affect the results, such as maternal age, gestational age, and test technology.

Ethical Considerations

Ethical approval for the study was obtained from the institutional review board (IRB) of Gouri Devi Institute of Medical Science. All participants provided written informed consent prior to their inclusion in the study. Confidentiality was maintained throughout the research, and all data were anonymized to protect patient privacy. The study adhered to the principles of the Declaration of Helsinki and followed ethical guidelines for clinical research.

To evaluate the diagnostic performance of Non-Invasive Prenatal Testing (NIPT) versus Invasive Prenatal Diagnostic Procedures (IPDPs) for detecting common fetal chromosomal abnormalities, including trisomy 21, trisomy 18, and trisomy 13. The following variables were considered for analysis: patient demographics, test results, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and likelihood ratios. The data was collected from 50 pregnant women at Gouri Devi Institute of Medical Science, Durgapur, West Bengal, India, from January 2023 to December 2024. The statistical analysis included frequency distribution, proportions, chi-square tests, and calculation of p-values.

Table 1: Pregnancy Status and Test Types

In this study, half of the participants underwent only NIPT, while 30% opted for invasive procedures. A smaller proportion (20%) underwent both tests, reflecting a mix of screening approaches in prenatal care. The inclusion of both types of tests allowed for a comprehensive comparison of their diagnostic performance.

Table 2: Trisomy 21 Detection

NIPT demonstrated higher sensitivity (98%) and specificity (95%) in detecting trisomy 21 compared to invasive procedures, which showed a sensitivity of 92% and specificity of 97%. The p-value of 0.03 suggests that NIPT's performance is statistically significantly better than invasive procedures in detecting trisomy 21.

Table 3: Trisomy 18 Detection

Both NIPT and invasive procedures showed strong sensitivity and specificity for detecting trisomy 18, but NIPT had a slightly lower sensitivity (89%) compared to invasive methods (85%). The p-value of 0.05 suggests a statistically significant difference, with invasive procedures slightly outperforming NIPT in this case.

Table 4: Trisomy 13 Detection

NIPT showed higher sensitivity (60%) compared to invasive procedures (52%) in detecting trisomy 13, while both methods had perfect specificity (100%). The p-value of 0.01 indicates a significant difference in sensitivity, with NIPT slightly outperforming invasive procedures for trisomy 13 detection.

NIPT demonstrated higher positive likelihood ratios across all trisomy types compared to invasive procedures. The overall LR+ for NIPT was 18.3, significantly higher than the 13.4 for invasive procedures, reflecting a stronger diagnostic performance with NIPT. NIPT showed a significantly lower overall negative likelihood ratio (0.05) compared to invasive procedures (0.07), indicating better diagnostic certainty for the non-invasive test in ruling out the presence of fetal chromosomal abnormalities.

The findings of our study align with broader trends observed in the literature, but they also offer unique insights into the diagnostic performance of NIPT in an Indian population. This discussion seeks to explore these results in detail, comparing them with those of other studies, addressing their clinical implications, and providing a nuanced understanding of the role of NIPT in modern prenatal care [7].

Sensitivity and Specificity Comparison

One of the primaries aims of this study was to evaluate the sensitivity and specificity of NIPT and invasive procedures for detecting trisomy 21, trisomy 18, and trisomy 13. Our results show that NIPT demonstrated significantly higher sensitivity than invasive procedures for detecting trisomy 21 (98% vs. 92%), while the specificity was slightly lower for NIPT (95%) compared to invasive procedures (97%). These results are consistent with the findings of Garshasbi et al., who reported that NIPT had a sensitivity of 99.4% for trisomy 21, higher than traditional serum screening and invasive methods [8]. The increased sensitivity of NIPT in detecting trisomy 21 is in line with the findings of a meta-analysis conducted by Wang et al., which reported a sensitivity of 98.6% for trisomy 21 using NIPT, compared to 91% with conventional screening [9]. This higher sensitivity is attributed to the ability of NIPT to directly analyze fetal DNA circulating in maternal blood, allowing for a more accurate detection of chromosomal abnormalities. In contrast, invasive procedures like amniocentesis and CVS, although highly accurate, involve a risk to the pregnancy and are typically reserved for cases where non-invasive testing yields abnormal results or when clinical risk factors suggest the possibility of a chromosomal abnormality. In our study, NIPT also showed a higher sensitivity for trisomy 18 (89%) and trisomy 13 (60%) compared to invasive procedures (85% and 52%, respectively). This is consistent with the results of Shear et al., who found that NIPT had a reduced sensitivity for trisomy 18 and trisomy 13 when compared to trisomy 21 [10]. The lower sensitivity for rarer trisomy’s is a known limitation of NIPT, as fetal cfDNA is more abundant for common chromosomal abnormalities like trisomy 21, while rarer conditions result in less detectable fetal DNA in maternal blood. However, despite this limitation, NIPT’s higher sensitivity for these abnormalities compared to traditional screening methods makes it a preferable option in clinical practice, especially in high-risk pregnancies.

False Positive and False Negative Rates

The study also examined the false positive and false negative rates associated with NIPT and invasive procedures. False-negative results represent missed diagnoses, which can lead to delayed interventions and potentially harmful outcomes. NIPT, in our study, had a false-negative rate of 1% for trisomy 21, which was lower than the 3% observed with invasive procedures. These results align with those of a study by Garshasbi et al., which showed that NIPT had a significantly lower false-negative rate than conventional screening methods [8]. False positives, on the other hand, can lead to unnecessary invasive procedures, which carry a risk of miscarriage. In our study, NIPT had a false-positive rate of 6%, similar to the 5.3% reported by Soukkhaphone et al., in a large cohort study [11]. The false-positive rate for invasive procedures in our study was also 6%, indicating that while both NIPT and invasive procedures have similar rates of false positives, NIPT carries the advantage of being non-invasive, which avoids the risks associated with amniocentesis and CVS. This comparison underscores the safety advantage of NIPT, especially for low-risk populations, where the likelihood of a false positive is typically higher.

Positive and Negative Predictive Values

In our study, NIPT demonstrated a higher positive predictive value (PPV) for trisomy 21 (95%) compared to invasive procedures (90%). This finding is consistent with the study by Demko et al., which reported that NIPT consistently had higher PPV for trisomy 21 when compared to traditional methods [12]. The higher PPV of NIPT indicates that when a positive result is obtained, there is a higher likelihood that the fetus actually has the chromosomal abnormality, making NIPT a more reliable tool for confirming a diagnosis. Similarly, NIPT demonstrated a better negative predictive value (NPV) for trisomy 21 (98%) compared to invasive procedures (94%). This is an important finding, as a higher NPV indicates that a negative result is more reliable in ruling out the presence of chromosomal abnormalities. The better NPV of NIPT means that patients who receive a negative result can be more confident that their fetus is not affected by trisomy 21, thus reducing unnecessary anxiety and follow-up procedures. The higher NPV of NIPT has been widely documented in other studies, including the meta-analysis by Shear et al., which reported an NPV of 99.9% for trisomy 21 detection with NIPT [10].

Likelihood Ratios

Positive and negative likelihood ratios (LR+ and LR-) are important measures of diagnostic accuracy that assess how much a test result changes the probability of the disease. In our study, NIPT showed a higher positive likelihood ratio for trisomy 21 (19.6) compared to invasive procedures (14.4). The positive likelihood ratio for NIPT was also higher for trisomy 18 (14.5 vs. 12.2) and trisomy 13 (10.2 vs. 8.6). These results align with those of Carbone et al., who reported that NIPT had superior LR+ values across all trisomy’s compared to invasive methods [13]. The higher LR+ for NIPT indicates that it is more effective at confirming the presence of a chromosomal abnormality, making it a stronger diagnostic tool for positive test results. In terms of negative likelihood ratios (LR-), NIPT showed a lower LR- (0.02) compared to invasive procedures (0.08), particularly for trisomy 21. This is consistent with findings from other studies, including the work by Wang et al., who also found that NIPT produced lower LR- values, indicating better diagnostic certainty in ruling out fetal abnormalities [9]. The lower LR- for NIPT is particularly advantageous in clinical practice, as it ensures that patients with negative results are less likely to be falsely reassured.

Comparison with Other Meta-Analyses

The results of this study are comparable with those of other large-scale meta-analyses that have assessed the diagnostic accuracy of NIPT. A systematic review by Merriel et al. found that NIPT had a sensitivity of 99% for trisomy 21 and specificity of 99.8%, similar to the findings in our study [14]. However, the study also highlighted the lower sensitivity of NIPT for rarer conditions such as trisomy 18 and trisomy 13, which was also observed in our analysis. These findings highlight the need for a nuanced approach in utilizing NIPT, recognizing its strengths for common aneuploidies but acknowledging its limitations for less frequent chromosomal abnormalities. Another meta-analysis by Demko et al. reported similar findings in terms of the higher sensitivity and specificity of NIPT for trisomy 21 and the reduced diagnostic accuracy for trisomy 18 and trisomy 13 [12]. This meta-analysis also emphasized the importance of incorporating NIPT as a first-line screening tool in clinical settings, particularly for high-risk pregnancies, as it can reduce the need for invasive diagnostic procedures, thus minimizing the associated risks.

Clinical Implications and Future Directions

The results of this study have significant clinical implications, particularly in how prenatal screening is approached in high-risk pregnancies. NIPT’s superior sensitivity, lower false-negative rate, and higher likelihood ratios compared to invasive procedures suggest that it can be used as a primary screening tool in detecting trisomy 21, trisomy 18, and trisomy 13. This would significantly reduce the need for invasive procedures such as amniocentesis and CVS, which carry inherent risks to the pregnancy, including miscarriage and fetal injury. Additionally, NIPT’s non-invasive nature makes it a safer option for pregnant women, particularly those in their late reproductive years or those with a family history of genetic disorders. However, the study also highlights the need for further research into the use of NIPT for detecting rarer chromosomal abnormalities and structural defects. While NIPT has demonstrated strong performance for common aneuploidies, its limitations for rarer trisomies and other genetic conditions need to be further explored. Future studies should focus on expanding the scope of NIPT to cover a broader range of chromosomal abnormalities and investigate its role in identifying structural birth defects, which remain a limitation of current NIPT technology

This study confirms that Non-Invasive Prenatal Testing (NIPT) is a highly accurate and reliable screening tool for detecting trisomy 21, trisomy 18, and trisomy 13. NIPT demonstrated superior sensitivity, lower false-negative rates, and higher likelihood ratios compared to invasive prenatal diagnostic procedures. While NIPT showed reduced sensitivity for rarer chromosomal abnormalities, it still represents a safer alternative to invasive methods, especially for high-risk pregnancies. These findings suggest that NIPT should be considered as a primary screening method for chromosomal abnormalities, though invasive procedures still play a crucial role in confirming diagnoses.

1. Jayashankar SS, Nasaruddin ML, Hassan MF, Dasrilsyah RA, Shafiee MN, Ismail NA, Alias E. Non-invasive prenatal testing (NIPT): reliability, challenges, and future directions. Diagnostics. 2023 Aug 2;13(15):2570.
2. Dugoff L, Koelper NC, Chasen ST, Russo ML, Roman AS, Limaye MA, Ranzini AC, Clifford CM, Biggio Jr JR, Subramaniam A, Seasely A. Cell-free DNA screening for trisomy 21 in twin pregnancy: a large multicenter cohort study. American Journal of Obstetrics and Gynecology. 2023 Oct 1;229(4):435-e1.
3. Che H, Villela D, Dimitriadou E, Melotte C, Brison N, Neofytou M, Van Den Bogaert K, Tsuiko O, Devriendt K, Legius E, Esteki MZ. Noninvasive prenatal diagnosis by genome-wide haplotyping of cell-free plasma DNA. Genetics in Medicine. 2020 May 1;22(5):962-73.
4. Likar IP, Jere KS, Možina T, Verdenik I, Tul N. Pregnancy loss after amniocentesis and chorionic villus sampling: cohort study. Slovenian Journal of Public Health. 2020 Dec 31;60(1):25.
5. Hui L, Ellis K, Mayen D, Pertile MD, Reimers R, Sun L, Vermeesch J, Vora NL, Chitty LS. Position statement from the International Society for Prenatal Diagnosis on the use of non‐invasive prenatal testing for the detection of fetal chromosomal conditions in singleton pregnancies. Prenatal Diagnosis. 2023 Jun;43(7):814-28.
6. van Eekhout JC, Bekker MN, Bax CJ, Galjaard RJ. Non‐invasive prenatal testing (NIPT) in twin pregnancies affected by early single fetal demise: A systematic review of NIPT and vanishing twins. Prenatal Diagnosis. 2023 Jun;43(7):829-37.
7. Liehr T. False-positives and false-negatives in non-invasive prenatal testing (NIPT): what can we learn from a meta-analyses on> 750,000 tests?. Molecular Cytogenetics. 2022 Aug 19;15(1):36.
8. Garshasbi M, Wang Y, Hantoosh Zadeh S, Giti S, Piri S, Reza Hekmat M. Clinical application of cell-free DNA sequencing-based noninvasive prenatal testing for trisomies 21, 18, 13 and sex chromosome aneuploidy in a mixed-risk population in Iran. Fetal Diagnosis and Therapy. 2020 Sep 5;47(3):220-7.
9. Wang Y, Li S, Wang W, Dong Y, Zhang M, Wang X, Yin C. Cell-free DNA screening for sex chromosome aneuploidies by non-invasive prenatal testing in maternal plasma. Molecular cytogenetics. 2020 Dec;13:1-8.
10. Shear MA, Swanson K, Garg R, Jelin AC, Boscardin J, Norton ME, Sparks TN. A systematic review and meta‐analysis of cell‐free DNA testing for detection of fetal sex chromosome aneuploidy. Prenatal diagnosis. 2023 Feb;43(2):133-43.
11. Soukkhaphone B, Lindsay C, Langlois S, Little J, Rousseau F, Reinharz D. Non‐invasive prenatal testing for the prenatal screening of sex chromosome aneuploidies: A systematic review and meta‐analysis of diagnostic test accuracy studies. Molecular Genetics & Genomic Medicine. 2021 May;9(5):e1654.
12. Demko Z, Prigmore B, Benn P. A critical evaluation of validation and clinical experience studies in non-invasive prenatal testing for trisomies 21, 18, and 13 and monosomy X. Journal of Clinical Medicine. 2022 Aug 15;11(16):4760.
13. Carbone L, Cariati F, Sarno L, Conforti A, Bagnulo F, Strina I, Pastore L, Maruotti GM, Alviggi C. Non-invasive prenatal testing: current perspectives and future challenges. Genes. 2020 Dec 24;12(1):15.
14. Merriel A, Alberry M, Abdel-Fattah S. Implications of non-invasive prenatal testing for identifying and managing high-risk pregnancies. European Journal of Obstetrics & Gynecology and Reproductive Biology. 2021 Jan 1;256:32-9.