Usually the left ventricle of the fetus is not completely closed and is not particularly serious when the area is small. If the area of non-occlusion is large or accompanied by serious cardiac malformations, further treatment is required. 1. Smaller unsealed area: If the unsealed area of the left ventricle is less than 12 mm, the defect will usually close with further fetal growth and development. Smaller defects will not have a significant impact on fetal heart function and do not require special treatment, and will usually close when the child is about half to one year old. 2. Large unclosed area, or accompanied by serious cardiac malformation: If the unclosed defect of fetal heart is larger than 12mm, or accompanied by serious cardiac malformation, usually the fetus has hypoxia, shock, heart failure and so on, which suggests that the situation is more serious, and it needs to be treated as soon as possible with appropriate methods, and it may lead to the death of the fetus if the treatment is not timely. Therefore, if the left ventricle of the fetus is not completely closed, it is not particularly serious, and pregnant women are advised to have regular checkups, pay attention to nutritional intake, and ensure a good state of rest. If the area of non-occlusion is large or accompanied by serious cardiac malformations, suggesting that the development of the fetus is affected, then it is recommended to follow the doctor’s advice for treatment.