Paediatrics (also spelled paediatrics or podiatric) is the branch of medicine that involves the medical care of infants, children, and adolescents. The American Academy of Paediatrics recommends people seek paediatric care through the age of 21. In the United Kingdom, paediatrics covers patients until age 18. Worldwide age limits of paediatrics have been trending up year over year. A medical doctor who specializes in this area is known as a paediatrician, or paediatrician. Paediatricians work in hospitals and children's hospitals particularly those working in its subspecialties (e.g. neonatology), and as outpatient primary care physicians.