Congenital heart disease (CHD) is the commonest single group of congenital abnormalities, accounting for about 30% of the total congenital anomalies.The etiology of congenital heart disease is multifactorial, with both genetic and environmental influences; there are some clear associations with chromosomal abnormalities. The prevalence of specific heart defect may vary considerably among geographic regions, owing to maternal age and risks and possibly genetic variation.Many of the major cardiovascular structural abnormalities occur in the 1st 6 to 7 weeks of human development; these defects include abnormalities of situs, defects of septation, and transposition of great arteries.Ventricular septal defects account for the largest proportion of heart defects (30.7%), followed by patent ductus arteriosus (13.5%), atrial septal defect (11.6%), pulmonary stenosis (7.5%), tetralogy of Fallot (7.4%), hypoplastic right heart syndrome (2.8%), aortic stenosis (2.4%), transposition of great arteries (2.4%), atrioventricular septal defects (2.0%) and single ventricle (0.4%).