Prenatal diagnosis of congenital heart defects: experience of the first Fetal Cardiology Unit in Mexico

Objective: The purpose of this article was to describe our experience with the prenatal diagnosis of CHD in patients referred to our Fetal Cardiology Unit. Methods: Prospective cohort study of consecutive fetuses referred for advanced fetal echocardiography to our Fetal Cardiology Unit during a 3-year period (September 2015-September 2018). Results: Totally 809 fetuses were evaluated, with 1263 fetal advanced echocardiographies performed. Suspected cardiac abnormality was the most common indication for referral (62.2%). Only 7.3% of patients had known morbidities or risk factors for CHD. Mean gestational age at first examination was 25.6 +/- 6.4 weeks. A total of 528 (65.3%) fetuses were found to have a cardiac defect: 40.7% had isolated CHD while 24.6% had associated anomalies. The most common defects found were ventricular septal defects (20.3%), followed by conotruncal defects (9.7%), hypoplastic left heart syndrome (9.3%), fetal arrhythmias (8.9%), and venous anomalies (8.7%). 31.6% presented abnormal genetic studies, the most frequent being Down syndrome (23/212, 10.8%), followed by DiGeorge syndrome (11/212, 5.2%). Conclusions: Prenatal screening and diagnosis of CHD in Mexico are feasible, with suspected cardiac abnormality being the main reason for referral to a specialized Fetal Cardiology Unit. Efforts must be made to make screening available to the general population in the first and second trimesters of pregnancy by fetal medicine or trained specialists, in order to identify fetal CHD and offer advanced echocardiography, genetic studies, timely fetal cardiac intervention in selected cases, and delivery in tertiary centers, to improve overall survival.