First trimester diagnosis of fetal cardiac anomalies: a sonopathological correlation study

Background: Accurate diagnosis of structural cardiac anomalies in the first trimester is critical due to its impact on anxiety and pregnancy management. This study aims to evaluate the correlation between first-trimester ultrasound (USG) findings of cardiac anomalies and perinatal pathological evaluations. Methods: This retrospective study was conducted at Mediscan systems, a tertiary care fetal medicine center in South India, analyzing first-trimester scans from January 2012 to December 2017. Singleton pregnancies with detected cardiac anomalies were identified from the sonocare database. Only those cases with subsequent perinatal autopsy were included in the study cohort. Results: In the study cohort, the mean maternal age was 26.6 years (range 19-44), mean BMI was 26.1 (range 17.5-42.8), and mean crown-rump length was 65 mm (range 48-82 mm). Ultrasound findings and autopsy results were in complete agreement in 62% of cases. Autopsies provided additional information in 28% of cases, while 10% of cases had discordant findings. Notably, the accuracy improved in the second cohort, with complete agreement rising from 49% to 76% and mismatches reducing from 21% to zero. Conclusions: The study highlights that a systematic checklist enhances the accuracy of first-trimester cardiac assessments, achieving correct diagnoses in 90% of cases. The improvement over time underscores the effectiveness of refined diagnostic protocols. Despite these advances, challenges in differentiating certain anomalies persist, but no prenatally diagnosed anomalies were found normal on autopsy, reinforcing the reliability of early diagnoses and the ability to provide confident counselling.