It is common for newborns to have heart murmurs. There are physiologic and pathologic factors that cause heart murmurs, and pathologic factors such as atrial septal defects and pulmonary stenosis. 1. Physiological factors: some of the fetal structures will be retained for a short period of time after birth, such as the ductus arteriosus, which is the blood flow channel between the pulmonary artery and the aorta during fetal life. If the ductus arteriosus does not close after birth, a heart murmur may occur. A heart murmur also occurs when the blood in the newborn’s heart accelerates in a vortex pattern. 2. Pathological factors: Atrial septal defects in newborns can lead to abnormal channels between the left and right atria, resulting in abnormal blood flow and increased friction sounds and heart murmurs. When the pulmonary artery stenosis, the pulmonary valve can not open completely, the blood in the heart will produce turbulence, which will lead to heart murmur. When a newborn develops a heart murmur, it is important to go to a specialist hospital immediately.