Infant mortality is the death of infants in the first year of life. Major causes of infant mortality include congenital malformation, infection and SIDS. Neonatal mortality is a subcategory which only includes deaths in the first 27 days of life. Post-neonatal death is a subcategory which only includes deaths after 28 days of life but before one year.
This epidemiological indicator is recognized as an important measure of the level of healthcare in a country because it is directly linked with the health status of infants, children, and pregnant women as well as access to medical care, socioeconomic conditions, and public health practices.
Newborn babies are born with their skin coated with a white substance known as vernix caseosa, which is hypothesized to act as an antibacterial barrier.
Feeding is done by breastfeeding or with special industrial milk, "infant formula". Babies have a sucking instinct allowing them to extract the milk from the nipples of the breasts or of the nipple of the baby bottle.
Breastfeeding provides babies with many natural immune substances and isolates the baby from most bacteria or other contaminations in the local water supply. Infant formula does not provide these immune substances and in places with poor quality water supply subjects the baby to disease which it would not be subjected to if breastfed. Public relations methods have been used to encourage the use of infant formula and increase profits for corporations which produce and sell the infant formula, despite negotiations between mothers' networks like Baby Milk Action, the World Health Organisation and corporations.
Babies are incontinent, therefore diapers are used.
Unlike other people, babies often cry without apparent cause.
As is the case of most of other young children, the social presence of infants is different from that of adult individuals. They are usually treated as special persons. They may be the focus of attention. On the other hand, fees of transportation and entrance fees are often less or nothing, possibly with requirements about who guides them. One reason is that e.g. a baby is taken in an amusement park not to have fun, or in a museum not to watch the artwork, but because it can not be left at home.
The term infant is also used as formal term for minor, i.e. child in general.