Does a ventricular septal defect affect development? For relatively small ventricular septal defects, such as those under five millimeters, the shunt from the left ventricle to the right ventricle is minimal, hence patients may not exhibit noticeable symptoms. However, if the defect is larger, for instance, over five millimeters, a large volume of blood will flow from the left ventricle into the right ventricular system. This causes congestion in the right ventricular system and the pulmonary circulation will be flooded with blood. As the saying goes, "flowing water does not rot, nor do door hinges become worm-eaten"; however, when a large amount of blood accumulates in the pulmonary vessels, patients are prone to recurrent respiratory infections and even congestive right heart failure, which then leads to feeding difficulties. Patients feel consistently uncomfortable and have difficulty breathing, so they may be reluctant to eat, especially in young children who need considerable effort to drink milk, which requires some breath-holding. At this time, patients experience feeding difficulties, which equates to developmental delays. Therefore, larger ventricular septal defects can affect a child's development. Small defects, such as those under three millimeters, might not affect development, but larger defects do impact development and thus require timely treatment.