How do parents know that their child may have congenital heart disease when they have not brought him or her to the doctor? Cyanosis of the child’s mouth, lips, fingernails or after crying is the easiest symptom to detect that is extremely closely related to heart disease. Babies with cyanosis right after birth often have complex congenital heart disease, such as tricuspid atresia, pulmonary atresia, transposition of the great arteries or severe trisomy of Fallot. If cyanosis appears a few months later, it is most likely to be tetralogy of Fallot. If cyanosis develops gradually in the first few years of life, in the late teens, or in adulthood, it may be a left-to-right shunt type of congenital heart disease, such as ventricular defect, unclosed ductus arteriosus with arterial hypertension. However, non-cyanotic congenital heart disease is often not easily recognized by parents in the early stage. If the child has poor growth and development within 1 year of age, is thin, often has pneumonia, shortness of breath after breastfeeding, blue around the mouth, and blossoming skin, the possibility of congenital heart disease should be noted and a doctor should be consulted promptly.