**5.1 Spontaneous closure**

Approximately 70% of ventricular septal defects do not require any intervention either due to spontaneous closure or due to hemodynamically insignificant shunts. Trabecular muscular VSDs tend to close more often than membranous defects. Most defects close by 2 years of age but in some cases, closure may take place through 8 years of age. However, the process of spontaneous closure continues through adolescence and adulthood. Membranous defects close due to apposition of tricuspid valve leaflets against the VSD; also described as "aneurysmal" formation [16].
