A four-chamber heart is a diagnostic cardiac ultrasound that is primarily used for cardiac ultrasound of the fetal heart during pregnancy. Four-chambered heart refers to the fact that through the ultrasound probe, it can be clearly found that there are four chambers in the heart of the pregnant baby, which are the left atrium, the left ventricle, the right atrium, and the right ventricle, arranged in a field shape. The diagnosis of having a four-chambered heart initially indicates that the baby’s heart is structurally normal with no obvious developmental abnormalities. However, for heart examination of babies during pregnancy, the results are limited to reference only and may have errors due to a variety of factors. Heart ultrasound examination is the most accurate after the baby is born. During pregnancy, according to the time of pregnancy, choose the appropriate examination program, to avoid missing early fetal developmental malformations that may occur, and respond early to any abnormalities.