The field of medicine that is concerned with the health of infants, children, and adolescents; their growth and development; and their opportunity to achieve full potential as adults. The word pediatrics and its cognates mean "healer of children". A pediatrician, who provides not only medical care for children who are acutely or chronically ill but also preventive health services for healthy children. pediatric cardiology, critical care medicine, endocrinology, gastroenterology, hematology, neonatal medicine and nephrology etc. are the Subspecialties in pediatrics.