Diagnosis of major cardiac defects through routine early pregnancy ultrasound examination.

OBJECTIVE: Early detection of major cardiac defects is crucial for the management and prognosis of affected pregnancies. This study evaluated the effectiveness of routine first-trimester ultrasounds in detecting major cardiac defects in singleton pregnancies. METHODS: This retrospective study (2015-2023) at a tertiary center included 35,230 singleton pregnancies undergoing routine ultrasounds at 11-14, 20-24, 28-34, and 34-38 weeks. High-resolution equipment and standardized protocols were used to assess fetal nuchal translucency and cardiac structure. RESULTS: Among the 35,230 pregnancies studied, 270 cases (0.8%) of major heart defects were identified. Hypoplastic left heart syndrome (HLHS) was detected in 31 cases with a 90% detection rate, while ventricular septal defects (VSD) were the most common, found in 128 cases with a lower detection rate of 16%. Pregnancy outcomes varied significantly with gestational age: 55.9% of early detections (11-13 weeks) led to termination, while 63.9% of mid-term detections (18-22 weeks) resulted in live births. The first-trimester ultrasound scans demonstrated 100% sensitivity and Negative Predictive Value (NPV), with a specificity of 93.85% and a Positive Predictive Value (PPV) of 90.27%. The Kappa value of 0.917 indicated moderate agreement between early and later scans. Notably, early diagnosis (11-13 weeks) was associated with a higher rate of pregnancy terminations, while later diagnoses corresponded to higher live birth rates. CONCLUSION: Routine first-trimester ultrasounds effectively detect major cardiac defects early. However, the high sensitivity but low specificity necessitates follow-up scans to confirm findings and reduce false positives, ultimately enhancing prenatal care.