First-Trimester Screening for Severe Congenital Heart Defects in High-Risk Fetuses: The French PréCaFoet Study

Introduction

Congenital heart defects (CHDs) are among the most common congenital anomalies, with significant postnatal mortality. Prenatal detection is crucial for preparing parents and healthcare providers for prognosis and management. In France, since 2022, the CNEOF guidelines recommend first-trimester cardiac ultrasound screening for all pregnancies, including low-risk cases. However, limited studies have evaluated the diagnostic accuracy of this approach in non-tertiary care settings.

Method

The PRéCaFoet study was a prospective multicenter cohort study conducted from November 2020 to May 2024 across 12 French centers. It aimed to assess the diagnostic performance of first-trimester screening for severe CHDs in high-risk pregnancies. Inclusion criteria included increased nuchal translucency (> 3.5 mm), first-degree family history of CHD, or suspicion of cardiac or extracardiac anomalies during routine first-trimester ultrasound. Diagnostic performance was evaluated using sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) compared to gold-standard second-trimester ultrasound or fetal autopsy.

Results

Among 401 eligible pregnancies analyzed, 375 had conclusive first-trimester reference ultrasounds (Echo Ref T1). Severe CHDs were detected in 33 fetuses at T1 and confirmed in 30 at T2. Sensitivity and specificity for severe CHD detection at T1 were 83.3% and 93%, respectively, with a PPV of 58.1% and an NPV of 98%. Sequential screening (Echo Ref T1 followed by fetal echocardiography in abdnormal or inconclusive cases) reduced non-contributive cases from 5.7% to 2.8%. Prognostic evaluation revealed significant uncertainties: among 40 severe CHD cases, cardiac type (univentricular vs. biventricular) remained undetermined in 37.5%, and curability could not be assessed in 37.5% of cases. Detection rates varied by defect type: univentricular defects (87.5%), transposition of the great arteries (100%), atrioventricular canal defects (75%), tetralogy of Fallot (50%), ventricular septal defects (25%), and total anomalous pulmonary venous return (0%).

Conclusion

First-trimester screening for severe CHDs demonstrated high sensitivity and specificity in a high-risk population within a non-tertiary care network. However, prognostic assessment at T1 proved challenging, with inconclusive classifications in over one-third of cases, underscoring limitations in early counseling for complex defects.