Table 1.
Illustrates the variable definitions used and overlap of different age groups of children
| Name | Definition |
|---|---|
| Preterm neonate | Period at birth when a newborn is born before full gestational period. |
| Term Neonate | Birth to 27 days. Newborn up to 1 month. A newborn infant, or neonate, is a child under 28 days of age. |
| Infant/Infancy | 28 days to 1 year of age. 1 month to 2 years. 0 to 1 year of age. |
| Toddler | 13 months to 2 years. 1 to 3 years. |
| Preschool child | 3 to 5 years. |
| Early childhood | 2 to 5 years. |
| Middle childhood | 6 to 11 years. |
| Child | 2 to 12 years. |
| Young teen | 12 to 14 years. |
| Teenager | 15 to 17 years. |
| Adolescent | 12 to 16 years. 10 to 19 years. |
| Early adolescence | 12 to 18 years. |
| Late adolescence | 19 to 21 years. |
a NICHD Eunice Kennedy Shriver National Institute of Child Health and Human Development
b FDA US Food and Drug Administration
c WHO World Health Organisation
d CDC Centers for Disease Control and Prevention