The foramen ovale is a vital channel necessary for fetal development, and it is through this channel that blood from the mother’s umbilical vein enters the left side of the fetal heart chambers and is then distributed throughout the body to provide the oxygen and nutrients necessary for fetal development. At birth, with the first cry, the pressure in the left atrium rises and the oval fossa valve is pressed against the edge of the oval fossa to form a functional closure, which is usually complete anatomically until 5 to 7 months after birth. Therefore, it is possible that the foramen ovale may remain open up to one year of age, and there may be a small shunt, or even 5%D10 % of individuals with the foramen ovale remaining open and unclosed for life, but with no effect on cardiac hemodynamics. Therefore, in infants, the patent foramen ovale is a normal physiological phenomenon, not a precordial disease, and usually does not require surgery. During fetal life, in order to maintain the circulation of the fetal left heart, the lower edge of the secondary atrial septum and the upper edge of the primary atrial septum are in contact with each other but do not fuse, leaving a crescent-shaped fissure at the tip of the foramen ovale that is not closed. The primary atrial septum acts as a valve, allowing only right-to-left diversion of blood and preventing left-to-right reversal of flow. After birth, the pressure in the left atrium is greater than that in the right atrium, causing the valve of the foramen ovale to close against the secondary septum and thus close the foramen ovale. Blood flow between the right and left atria is usually completely cut off by the eighth month of life or longer. However, in 20%-25% of normal individuals, the foramen ovale valve and the septum do not completely fuse, leaving a small potential fissure known as an unclosed foramen ovale. This usually does not cause a shunt between the two interatrial compartments and is not hemodynamically significant, so surgical treatment is not required. The fetal heart develops gradually. The primitive heart is a longitudinal straight tube, and some of the atria and ventricles can be distinguished by the 4th week as the embryo develops. If the interatrial septum does not completely adhere to the endocardial cushion during growth at 5 to 6 weeks, an orifice is left in the right and left atria, which is the foramen ovale. During fetal life, fetal blood circulation requires the use of the foramen ovale to allow a portion of blood to flow from the right atrium to the left atrium. After the baby is born, with the disconnection of the umbilical vessels and the establishment of the newborn’s own pulmonary circulation, the pressure in the left atrium is higher than that in the right atrium, and the blood from the right atrium does not flow into the left atrium, and the foramen ovale is functionally closed. If the mother has contracted a virus during pregnancy, has been exposed to radiation or has taken medications that impair fetal development, the foramen ovale may not close, resulting in a congenital right ventricular septal defect, and a heart repair after birth. However, the condition is less severe than other atrial septal defects. If the symptoms are mild, surgery is not necessary, as there are normal babies with unclosed foramen ovale. However, if the symptoms are significant and the blood flow from left to right is high, surgical repair should be performed when the baby is 2 to 4 years old. If the baby is less than 1 year old, the foramen ovale does not usually need to be treated because most of them can close on their own. Secondly, if it does not close on its own after the age of 2, then surgical closure can be considered, either surgical or interventional, and even because it is not uncommon for the foramen ovale to not close, you just don’t close it for life, and then most of them may not have anything major to do with it. The possible impact on the body is the presence of abnormal traffic in the first left and right atria, the potential future may be prone to brain embolism (cerebral infarction) in old age in addition to the migraines found in recent years in some people may also be related to this. Therefore, it is not too worrying if a newborn baby is found to have an unclosed foramen ovale.