**2. Indications and settings for fetal echocardiography (FECG)**

A detailed sonographic examination, used to characterize fetal cardiac anatomy has traditionally been reserved for high-risk populations [18–22]: advanced maternal age, more than 35 years old, family history of CHD or disorders that involves potential CHD, infectious, autoimmune or metabolic diseases, exposure to drugs and teratogens. FECG was also proposed in certain pregnancy findings: structural defects, non-immune hydrops, arrhythmia, suspected chromosomal abnormalities, enlarged nuchal translucency, monochorionic multiple gestation. Nowadays, professional guidelines recommend a screening heart evaluation to all pregnancies, as most of the CHD cases are not associated with known risk factors [38–45].

Guidelines and training requirements have been developed [18, 19]. An accurate visualization of heat features is commonly achieved at 18–22 gestational weeks. FECG is a relatively brief but skilled ultrasound examination, because of the complexity and prenatal physiological and structural particularities of the fetal heart. Consequently, FECG has not been widely implemented, and the prenatal diagnosis of even severe CHD varies considerably, with less than half prenatally detected.
