Explain Spontaneous Closure of Defects in details?

Some defects have a tendency towards spontaneous closure and this can influence the timing of intervention. The defects known to close spontaneously are atrial and ventricular septa1 defects and during the first few weeks of life, patent arterial duck. The variables that influence likelihood of spontaneous closure include, age at evaluation (the likelihood of spontaneous closure declines with age and most ASDs and many VSDs are unlikely to close after the first three years of age), size of the defect (smaller defects are more likely to close), location of the defects (fossa ovalis ASDs, perimembranous and muscular VSDs can close on their own).