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Infant Mortality


Updated January 12, 2012

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Infant mortality is a measure of the number of children who die under the age of one in a given year. It is given as a rate per 1,000 births, but is often reported as a single number. For example, in the years 2005-2007, the infant mortality rate for the State of New York would be reported as 5.7, which means an average of 5.7 children for every 1,000 children under the age of 1 died. Infant mortality rates are usually calculated using an average of several years of data so that an unexpected event, such as an epidemic, cannot significantly affect a country’s reported rate.

Infant mortality is used in many social sciences to compare the relative health of any given population. It is considered a benchmark for the population’s general well-being, since infant death is associated with many society-wide risk factors, such as low socioeconomic status, access to clean drinking water, access to health care, war, communicable diseases, and more.

Leading causes of death for children worldwide include dehydration, malnutrition, malaria, congenital malformations, and complications of infectious diseases like diarrhea, fever, and pneumonia. In the United States, congenital abnormalities are the number one cause of death in infants, followed by preterm delivery, SIDS, maternal complications in pregnancy, and problems with the umbilical cord, placenta, or bag of waters.

Infant mortality can be used to compare the relative health of populations around the world; however, not every country uses the same criteria to define infant death. For example, in the United States, a baby is considered “alive” at the time of birth if he or she shows any signs of life including breathing, a heartbeat, or voluntary movement. Other countries, including Japan, and many countries in Europe, only qualify a baby as “alive” if they are breathing after birth. Rates of perinatal mortality -- and death between viability and 7 days of life -- may be more helpful in comparing two populations.

Centers for Disease Control. NCHS Data Brief: Behind International Rankings of Infant Mortality: How the United States Compares with Europe. Accessed: 9 Jan 2012. http://www.cdc.gov/nchs/data/databriefs/db23.htm
Kaiser Family Foundation. “Infant Mortality Rates.” www.statehealthfacts.org Accessed: 9 Jan 2012.
Thomas, C., ed. Taber’s Cyclopedic Medical Dictionary, 18th Edition. 1997.

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