Diagnosis and retrospective characterization of fetal congenital heart disease in the Fetal Examination Unit between 2018-2025.

Abstract

Introduction: The incidence of CHD (congenital heart disease) in live births is 8 per 1,000. Published data from Chile indicate that 25-30% are diagnosed prenatally.

Objective: To describe and characterize moderate and complex CHD diagnosed prenatally by fetal echocardiography in the Fetal Examination Unit of the Guillermo Grant Benavente Regional Hospital, between January 2018 and March 2025.

Method: An observational, descriptive, and retrospective study. All cases with a confirmed prenatal diagnosis of moderate and complex CHD referred to tertiary care for management during the indicated period were included. Maternal variables, fetal ultrasound findings, genetic studies, and neonatal outcomes were analyzed until the end of follow-up. Survival was assessed using Kaplan–Meier curves.

Results: Eighty cases were analyzed: one corresponded to complete atrioventricular block requiring a pacemaker and 79 to structural heart disease. 63.8% were male fetuses. The most common entities were transposition of the great arteries (24.1%), hypoplastic left ventricular syndrome (16.5%), and coarctation of the aorta (10.1%). Twenty-one diagnostic combinations were documented (26.6%), the most common being double outlet right ventricle with transposition of the great arteries. Genetic studies were performed in 39 cases (48.8%), identifying chromosomal abnormalities in 13 (16.3%), primarily trisomy 21. Comorbidities were reported in 27 pregnant women (33.8%), most notably diabetes (n=8) and hypothyroidism (n=7). Seventy percent of the patients underwent neonatal cardiovascular surgery. Seventeen deaths (21.3%) were recorded, including one stillbirth and 16 postnatal deaths. Overall survival at the end of follow-up was 78.8%. The Kaplan–Meier curve showed a pronounced decline during the first month of life and subsequent stability.

Conclusion: The findings reveal a high frequency of critical injuries, a significant proportion of chromosomal abnormalities, and a significant burden of maternal comorbidities, including hypothyroidism. The survival rate reflects advances in neonatal cardiovascular diagnosis and surgery.