Prenatal detection of congenital heart disease at 12-13 gestational weeks: detailed analysis of false-negative cases

Simplified First-Trimester Fetal Cardiac Screening Protocol for Low-Risk Pregnancies: Enhancing Efficiency and Accuracy

Introduction

Congenital heart defects (CHDs) are among the most prevalent congenital anomalies and are frequently detected in pregnancies classified as low-risk, rather than in high-risk groups. Advancements in ultrasound technology have heightened the emphasis on first-trimester fetal cardiac screening. However, due to the small size of the fetal heart at this stage, significant challenges persist, underscoring the need for simplified and reproducible protocols that can be effectively applied on a population-wide scale.

Methods

This paper describes a screening approach centred on the four-chamber view (4CV) and three-vessel tracheal view (3VTV) with colour Doppler imaging. This includes optimisation of ultrasound machine settings and the use of transabdominal and transvaginal approaches to enhance visualisation.

Results

Evidence demonstrates a CHD detection rate of 76% in low-risk populations, with a 95% success rate in obtaining the necessary views.

Discussion and Conclusion

Operator expertise and familiarity with cardiac anomalies are critical for accurate detection. The early identification of CHDs enables informed decision-making regarding pregnancy management. A simplified protocol for first-trimester cardiac screening offers a promising tool for the early identification of CHDs, enabling timely referral and intervention. To optimise detection rates and clinical outcomes, continuous professional education and systematic auditing processes are indispensable for practitioners performing early fetal cardiac screening.

Evaluation of first-trimester ultrasound screening strategy for fetal congenital heart disease

OBJECTIVE

To assess the performance of a standardized first-trimester ultrasound screening strategy for fetal congenital heart disease (CHD).

METHODS

This was a large retrospective study involving 74 839 consecutive mixed-risk pregnancies (77 396 fetuses). Routine ultrasound scans at 11 + 0 to 13 + 6 weeks' gestation were performed in a single center from January 2015 to June 2023. All fetuses were examined using a predefined standardized ultrasound scanning strategy with adjustment of imaging parameters, which included assessment of the fetal heart. The ultrasound results (e.g. extracardiac congenital malformations), ultrasound markers (e.g. nuchal translucency thickening, reversed a-wave in the ductus venosus and tricuspid regurgitation), follow-up, genetic tests and diagnostic results were recorded and analyzed.

RESULTS

In total, there were 831 cases of CHD, with an incidence of 1.07% (831/77 396). In the first-trimester scan, 590 fetuses were diagnosed with CHD, but four were confirmed as normal in later examinations. In addition, 245 cases were missed. The detection rate was 70.52%, with a sensitivity, specificity, false-positive rate and false-negative rate of 70.52%, 99.99%, 0.01% and 29.48%, respectively. In fetuses with negative ultrasound markers and no extracardiac malformations, the detection rate of CHD was 45.79% (185/404). There were 281 cases that underwent karyotyping and chromosomal microarray (245 fetuses) or whole-exome sequencing (36 fetuses). In total, 38.79% (109/281) had a positive genetic test result. There were 273/831 CHD cases associated with extracardiac malformations. The abnormal image patterns and abnormal features of each view in the scanning strategy were summarized.

CONCLUSIONS

Ultrasound screening for fetal CHD in the first trimester of pregnancy enables earlier prenatal diagnosis and consultation. The standardized ultrasound screening strategy used in this study had a high detection rate for fetal CHD in the first trimester. Our proposed fetal heart screening strategy shows promising effectiveness for early diagnosis of CHD and we recommend its use. It is important to note, however, that first-trimester ultrasound screening for fetal CHD should not replace fetal echocardiography in the second trimester. © 2025 International Society of Ultrasound in Obstetrics and Gynecology.

Second trimester echocardiography

Fetal echocardiography involves a comprehensive cardiac assessment aiming to make a complete structural examination of the heart as well as to detect signs of cardiovascular adaptation to different insults. For the former, this assessment entails expert's evaluation of the anatomy of the heart including additional views beyond the five axial views used in cardiac screening examinations and always complemented with colour and pulsed Doppler. Echocardiography may accurately diagnose most congenital heart defects in fetal life, which enables adjusting the perinatal management. For the latter, echocardiography encompasses cardiac morphometric assessment to identify signs of cardiac remodeling indicative of cardiac adaptation in structure, shape, and size in response to underlying diseases, and cardiac functional assessment to detect signs of systolic and/or diastolic dysfunction. The most used parameters to study the systolic function (stroke volume, cardiac output, ejection fraction, fractional shortening, and mitral and tricuspid annular plane systolic excursion), diastolic function (characteristics of flow in the precordial veins and through the atrioventricular valves) and global myocardial function (myocardial performance index) will be discussed in this review.

Factors affecting the accuracy of fetal cardiac ultrasound screening in the first trimester of pregnancy

PURPOSE

Most studies on the performance of first-trimester cardiac screening have concentrated on comparing the detection rate between different protocols and not on the actual reason for false-negative results. Herein, we report the performance of first-trimester congenital heart disease (CHD) screening and factors that may affect the detection rate of CHDs.

METHODS

This retrospective observational study included patients who underwent first-trimester screening and subsequently gave birth at our facility. We analyzed the performance of first-trimester screening for CHD and major CHD (CHD requiring cardiac surgery or interventional catheterization within 12 months of birth).

RESULTS

Of the 6614 fetuses included, 53 had CHD and 35 had major CHD. For the prenatal diagnosis of CHD, the detection rate, specificity, positive predictive value, negative predictive value, and first-trimester detection rate for CHD were 64.1%, 99.9%, 94.4%, 99.7%, and 82.9%, respectively; the respective values for major CHD were 85.7%, 99.96%, 93.75%, 99.92%, and 85.7%. The detection rate was not significantly different when classified by crown-rump length or number of fetuses. A weak correlation was observed between low detection rate of major CHD and lower maternal body mass index (BMI) (correlation ratio: 0.17). The detection rate was significantly higher when the fetus was scanned with its spine at the 5-7 o'clock position (posterior spine) than at other positions (odds ratio: 3.82, 95% confidence interval: 1.16-12.5, p = 0.02).

CONCLUSION

Posterior spine contributes to an improved diagnostic rate in first-trimester CHD screening. In addition, sonographers must recognize that low maternal BMI is a risk factor of false-negative results.

False-Positive Diagnosis of Congenital Heart Defects at First-Trimester Ultrasound: An Italian Multicentric Study

Objective. Our objective was to assess the proportion of false-positive CHD cases at the first-trimester evaluation of the fetal heart, performed by experienced operators. Methods. This multicenter retrospective study included of pregnant women with suspicion of CHDs during first-trimester screening for aneuploidies. In all cases, the fetal heart assessments were performed by obstetricians with extensive experience in first-trimester scanning, following an extended protocol proposed by SIEOG national guidelines, which included an axial view of the fetal abdomen and chest to assess visceral situs and evaluation of the four-chamber view (4CV) and three-vessel trachea view (3VTV) with color Doppler. In all suspected cases, fetal echocardiography was offered within 16 and/or at 19-22 weeks' gestation. Results. From a population of 4300 fetuses, 46 CHDs were suspected. Twenty-four cases were excluded from this analysis because the parents opted for early termination of the pregnancies due to associated structural and/or genetic anomalies. For the remaining 22, echocardiography was performed by 16 weeks in 14 cases (64%) and after 16 weeks in 8 cases. In 19 cases (86.4%), a fetal cardiologist confirmed the presence of a CHD. In three cases (13%), the cardiac anatomy was found to be normal at the fetal echocardiography and postnatally. Conclusions. This study shows that the proportion of false-positive cases at the first-trimester ultrasound examination of the fetal heart, performed by experienced operators, may carry a higher risk of false-positive diagnosis than expected. Therefore, this issue must be discussed in instances where a CHD is suspected at the first-trimester screening.

The Holy Grail of obstetric ultrasound: can artificial intelligence detect hard-to-identify fetal cardiac anomalies?

Linked article: This Editorial comments on articles by Day et al. and Taksøe‐Vester et al.

Clinical implementation of first trimester screening for congenital heart defects

OBJECTIVE

To examine the feasibility and performance of implementing a standardized fetal cardiac scan at the time of a routine first-trimester ultrasound scan.

METHOD

A retrospective, single-center study in an unselected population between March 2021 and July 2022. A standardized cardiac scan protocol consisting of a four-chamber and 3-vessel trachea view with color Doppler was implemented as part of the routine first-trimester scan. Sonographers were asked to categorize the fetal heart anatomy. Data were stratified into two groups based on the possibility of evaluating the fetal heart. The influence of maternal and fetal characteristics and the detection of major congenital heart disease were investigated.

RESULTS

A total of 5083 fetuses were included. The fetal heart evaluation was completed in 84.9%. The proportion of successful scans increased throughout the study period from 76% in the first month to 92% in the last month. High maternal body mass index and early gestational age at scan significantly decreased the feasibility. The first-trimester detection of major congenital heart defects was 7/16, of which four cases were identified by the cardiac scan protocol with no false-positive cases.

CONCLUSION

First-trimester evaluation of the fetal heart by a standardized scan protocol is feasible to implement in daily practice. It can contribute to the earlier detection of congenital heart defects at a very low false positive rate.

First-Trimester Ultrasound Screening in Routine Obstetric Practice

Technologic advances and ultrasonographer-physician experience in fetal imaging have led to significant improvements in our ability to distinguish between normal and abnormal fetal structural development in the latter part of the first trimester. As a critical component of pregnancy care, assessment of fetal anatomy at the end of the first trimester with a standardized imaging protocol should be offered to all pregnant patients regardless of aneuploidy screening results because it has been demonstrated to identify approximately half of fetal structural malformations. Early identification of abnormalities allows focused genetic counseling, timely diagnostic testing, and subspecialist consultation. In addition, a normal ultrasound examination result offers some degree of reassurance to most patients. Use of cell-free DNA alone for aneuploidy screening while foregoing an accompanying early anatomic evaluation of the fetus will result in many anomalies that are typically detected in the first trimester not being identified until later in pregnancy, thus potentially diminishing the quality of obstetric care for pregnant individuals and possibly limiting their reproductive options, including pregnancy termination.

The Lifelong Impact of Artificial Intelligence and Clinical Prediction Models on Patients With Tetralogy of Fallot

Medical advancements in the diagnosis, surgical techniques, perioperative care, and continued care throughout childhood have transformed the outlook for individuals with tetralogy of Fallot (TOF), improving survival and shifting the perspective towards lifelong care. However, with a growing population of survivors, longstanding challenges have been accentuated, and new challenges have surfaced, necessitating a re-evaluation of TOF care. Availability of prenatal diagnostics, insufficient information from traditional imaging techniques, previously unforeseen medical complications, and debates surrounding optimal timing and indications for reintervention are among the emerging issues. To address these challenges, the integration of artificial intelligence and machine learning holds great promise as they have the potential to revolutionize patient management and positively impact lifelong outcomes for individuals with TOF. Innovative applications of artificial intelligence and machine learning have spanned across multiple domains of TOF care, including screening and diagnosis, automated image processing and interpretation, clinical risk stratification, and planning and performing cardiac interventions. By embracing these advancements and incorporating them into routine clinical practice, personalized medicine could be delivered, leading to the best possible outcomes for patients. In this review, we provide an overview of these evolving applications and emphasize the challenges, limitations, and future potential for integrating them into clinical care.