- infant mortality rate
- (IMR)the number of deaths of infants under one year of age per 1000 live births in a given year. Included in the IMR are the neonatal mortality rate (calculated from deaths occurring in the first four weeks of life) and postneonatal mortality rate (from deaths in the remainder of the first year). Neonatal deaths are further subdivided into early (first week) and late (second, third, and fourth weeks). In prosperous countries neonatal deaths account for about two-thirds of infant mortalities, the majority being in the first week (in the UK the major cause is prematurity and related problems). The IMR is usually regarded more as a measure of social affluence than a measure of the quality of antenatal and/or obstetric care; the latter is more truly reflected in the perinatal mortality rate (the number of deaths after 24 weeks of gestation, including stillbirths, and during the first week of life per 1000 total births). See also stillbirth.
Medical dictionary. 2011.