Infant Mortality

The neonatal mortality rate (NMR) is a calculation of the number of deaths that occur between birth and 28 days of age. The calculation of the rate is simply

NMR = (number of deaths from birth through 27 days, 23 hours, 59 minutes of age × 1000)/(number of live births during the same period of time)

In contrast, the postneonatal mortality rate covers deaths from 28 days of age up to 1 year of age. Combining neonatal mortality and postneonatal mortality creates the infant mortality rate (IMR). Both NMR and IMR are key measures of efforts aimed at improving public health outcomes.

The United States and other developed countries made great strides at reducing the IMR during the 20th century. The Centers for Disease Control (CDC) have hailed these strides as one of the 10 great medical achievements of the century. Between 1900 and 1999, the IMR decreased from 100 deaths per 1000 live births to 7/1000 live births in the United States. There has been a somewhat disparate improvement, as evidenced by a rate of 5.8/1000 among white births and 14/1000 in the black population. Despite these strides, the United States still lags behind more than 20 other countries in IMR. This is thought to be attributable to low early access and/or use of perinatal care for certain high-risk pregnancies. Further improvement continues to be a high priority sought by many public and private health initiatives. Currently the main focus of these efforts is to continue to reduce teen pregnancies while improving the early initiation of care during pregnancy.