There is no fixed value for the extent of ventricular septal defects in newborns. Ventricular septal defects can be categorized into small ventricular septal defects, medium-sized ventricular septal defects, large ventricular septal defects, etc., and the extent of the defects varies depending on the type. 1. Small ventricular septal defect: the diameter of the defect is less than 5mm or the area of the defect is less than 0.5cm²/m² of the body surface area, the left-to-right shunt flow is small, the hemodynamic change is not big, and there may be no symptoms, and the prognosis is generally good. 2. Medium-sized ventricular septal defect: the diameter of the defect is <5mm or the area of the defect is <0.5cm²/m² body surface area, the left-to-right shunt flow is small, hemodynamic changes are not big, and it can be asymptomatic. In severe cases, surgery is needed. 3. Large ventricular septal defect: the diameter of the defect＞10mm or the defect area＞1.0cm²/m² body surface area, left to right shunt flow is large, there may be more growth retardation, weight gain, feeding difficulties, susceptible to recurrent respiratory infections, easy to lead to congestive heart failure, etc., and most need early surgical treatment. Newborns with ventricular septal defects should be taken seriously, and it is recommended that standardized diagnosis and treatment be carried out as soon as possible under the guidance of professional doctors.