Baby’s patent foramen ovale is not closed 1mm Arterial Ductus Arteriosus 1mm is usually not serious and can be followed up for observation. The baby’s patent foramen ovale is the mildest type of congenital heart disease in children and is not serious; the patent foramen ovale is a unidirectional open hole in the process of septum formation; its physiological function is that when the baby is in the mother’s uterus, the baby’s umbilical cord blood arrives at the left heart through the patent foramen ovale, and then the blood is distributed from the left heart to the whole body. When the baby is delivered, the baby’s lungs open, the pressure in the pulmonary circulation drops dramatically, the pressure in the left heart rises significantly, and the unidirectional blood flow effect of the foramen ovale is no longer needed. However, the pressure in the baby’s pulmonary circulation does not drop sharply for various reasons, and the foramen ovale does not close completely. This is an unclosed foramen ovale, which has little effect on the baby’s circulatory system. If there is any abnormality in the clinic, it is necessary to go to the hospital for examination and treatment under the guidance of the doctor.