Of all the ways in which childhood has changed since premodern times, perhaps the most significant has been the dramatic decrease in the likelihood of dying during the first year of life. Although we can only estimate levels and trends of infant mortality prior to the most recent centuries, it seems probable that through much of human history 30 to 40 percent of all infants born died before they could celebrate their first birthdays. Today, in even the most underdeveloped and high-mortality regions of the world, barely a tenth do. And in the most developed and wealthiest regions less than 1 percent of infants fail to survive their first year. The vast majority of this sharp reduction in infant mortality took place in the twentieth century. Among today's highly developed nations, the major improvement in infant survival came prior to World War II. In the less developed nations, almost all the improvement has come since the war. In both sets of nations, mortality first dropped among older infants and then only later, if at all, among newborns.
The term infant mortality is generally understood to refer to the incidence of death among infants less than one year of age. When demographers attempt to chart the levels and trends of that mortality, they employ a number of statistics, most notably infant, neonatal, and post-neonatal mortality rates. These are standardized measures unaffected by differences in the proportion of infants in a given population. The infant mortality rate is the annual number of deaths among infants less than one year old per thousand live births. This measure is similar but not identical to what is called the infant death rate, which is the ratio of infant deaths to infants living and is somewhat higher. The neonatal mortality rate is calculated as the annual number of deaths of infants less than twenty-eight days old per hundred thousand live births. It is generally accepted that most of the deaths during this period are from endogenous causes; that is from congenital anomalies, gestational immaturity, birth complications, or other physiological problems. The post-neonatal mortality rate is computed similarly but describes the death rate of infants twenty-eight days to one year. In much of the world, the vast majority of deaths during this period continue to be from exogenous causes; that is, from injuries and from environmental and nutritional factors, especially as they interact with infectious disease like gastroenteritis and pneumonia. In the more highly developed nations, however, control of infectious disease and nutritional disorders has reached such a level that an ever-increasing proportion of post-neonatal deaths are attributable to endogenous causes.
What we know about the historical mortality patterns of today's highly developed nations suggests that through the seventeenth century infant mortality averaged between 20 and 40 percent and fluctuated substantially from year to year, occasionally hitting extremely high peaks when EPIDEMICS, famines, and war created mortality crises for the general population. Highly dependent on levels of maternal nutrition and general health as well as on the local sanitary and disease environments, infant mortality also varied significantly from place to place. In isolated rural villages in seventeenth-century England and New England, as few as 15 percent of all infants born may have perished in their first year. At the same time, their counterparts born in seaports, where sanitation was poor and where there was commerce in people, goods, and infectious diseases, probably died at over twice that rate. In the Americas and in southern Europe the presence of malaria could push infant mortality to over 50 percent. So too could the introduction of new diseases. Following the arrival of Europeans and then Africans in the New World, the aboriginal populations of the Americas were decimated by exposure to diseases to which they had no acquired or inherited immunities. In short, nothing so characterized levels of infant mortality in the premodern era as their variability across time and place.
That variability continued into the early eighteenth century, when the yearly fluctuations began to decrease, the periodic peaks became less frequent, and the differences between localities diminished. In a few places, a slight secular downward trend took place, but for the most part the period saw the stabilization rather than the lowering of infant mortality. Contributing to the homogenization and stabilization of infant mortality rates were the concomitants of economic development. Improvements in transportation made travel to rural villages less difficult and time consuming, increasing the communication of diseases from place to place and thus decreasing the likelihood that isolated pockets of low infant mortality could exist. Better urban sanitation, improvements in housing, and the more even distribution of foodstuffs, the filling and draining of swamps, and, perhaps, a world-wide southward retreat of malaria all helped make it less true for infants that being born in certain years and certain places constituted a death threat that would be enacted within a year's time. Of course, variability by time and place did not disappear; it only decreased. Seaports and cities were still
TABLE 1
more inimical to infant life than the countryside. And epidemics of smallpox, yellow fever, and other infectious diseases could still produce spikes of infant and general mortality. Additionally, considerable evidence exists that cultural differences in child rearing–particularly infant feeding practices–may have contributed significantly to higher rates in some areas than others.
The trend toward stabilization and conformity continued until the effects of early industrialization and urbanization began to be felt in the mid- to late eighteenth century. Industrialization brought increased wealth and higher living standards, but it also created industrial towns and massive cities which contained a significant underclass whose health was compromised by the social and biological pathologies that attend grinding poverty and filthy, overcrowded, disease-infested urban slums. For infants, it seems that initially the positive consequences of industrialization outweighed the negative ones. Although the evidence is not abundant, it is probable that infant survival improved in England through the third quarter of the eighteenth century and in western Europe and the United States during the forty years following 1790. It is also probable that by the middle of the nineteenth century, infant mortality rates were rising again as urbanization, industrialization, and the migration of workers and their families worsened sanitation and environmental pollution, made infant care more difficult, and increased the likelihood that pregnant women and infants would be exposed to dangerous diseases or toxins.
Indeed, late-nineteenth-century cities and industrial towns were deadly locales for infants, where 20 to 35 percent of all those born died within twelve months and where summer epidemics of gastroenteritis and diarrhea turned densely packed neighborhoods into infant abattoirs. As the New York Times editorialized in 1876 after one particularly deadly July week in which over a hundred infants a day had died in Manhattan: "There is no more depressing feature about our American cities than the annual slaughter of little children of which they are the scene" (quoted in Meckel, p. 11). Growing public concern throughout the industrialized West over this annual slaughter helped precipitate a public health movement to improve infant health and survival. Along with a complex amalgam of socioeconomic, environmental, and medical developments at the end of the nineteenth century, that movement started infant and child death rates on the path of decline that they would follow through the twentieth century and into the twenty-first.
As the twentieth century opened, infant mortality throughout much of the industrialized world had begun to drop. Nevertheless infant survival was still precarious, especially in eastern Europe. As table 1 shows, the probability of dying in infancy ranged from less than 10 percent in Scandinavia to over 22 percent in Austria, Czechoslovakia, and European Russia. In the United States the rate was approximately 12 percent. By the middle of the twentieth century it had declined significantly. In North America, northern Europe, and Australia it was less than 3 percent. In western Europe it was less than 5 percent and in eastern and southern Europe less than 9 percent. Much of that decline came among post-neonates, initially from a reduction in gastroenteric and diarrheal disorders and then from control of respiratory diseases.
Behind this reduction lay several developments. Prior to the 1930s, declining fertility and better nutrition and housing, accompanied by a rising standard of living, played important roles in reducing infant mortality. So too did environmental improvements brought about by the publicly funded construction of sanitary water supply and sewage systems and the implementation of effective refuse removal, particularly in urban areas. Also crucial was the work of public health officials and their allies in medicine and social work in controlling milk-borne diseases and educating the public in the basics of preventive and infant HYGIENE. Indeed, in the first three decades of the twentieth century, all the industrial nations of the world were the sites of major public health campaigns aimed at dramatically reducing infant mortality.
For many of the same reasons that it declined during the first third of the century, infant mortality continued to fall during the second. However, beginning in the 1930s the development and application of medical interventions and technologies played an increasingly large role in driving down infant death rates. Particularly important were the development, production, and dissemination of effective immunizations and drug therapies to combat the incidence and deadliness of infectious and parasitic diseases. Also important were significant improvements in both the techniques and technologies available to manage or correct life-threatening diseases or health problems. Among the most important of these were the perfection and widespread us of electrolyte and fluid therapy to counter the acidosis and dehydration that is often a consequence of serious bouts of diarrhea and enteritis; the increasingly sophisticated preventive and therapeutic use of vitamins to aid metabolism and combat nutritional diseases; and the development of increasingly safe and effective obstetric and surgical techniques to facilitate problem births and correct the consequences of congenital malformations.
In the last third of the twentieth century, the decline of mortality among older infants slowed to a snail's pace. Among neonates, however, it quickened precipitously, falling over 50 percent in some developed nations. Driving neonatal mortality down was an intense international effort to develop and make widely available various sociomedical programs and specific techniques and technologies to increase the survival rate of neonates, who deaths had come to constitute the bulk of infant mortality in the developed nations. That effort resulted in the perfection of diagnostic techniques and drugs that have proven effective in regulating pregnancy and preventing premature labor, and in the development of sophisticated surgical, therapeutic, and intensive care techniques and technologies to correct congenital deformities and to counter the risks faced by low birth-weight and premature babies. It also resulted in significant improvements in both the quality and availability of nutritional, prenatal, and natal care. As a consequence of a century of profound decline in infant mortality, babies born in the late twentieth century in developed nations enjoyed a probability of surviving their first year unimaginable through most of human history.
As the second half of the twentieth century began, life expectancy in the less developed nations of the world was not much better than it had been for centuries, largely because infant mortality remained astronomical. Some areas, of course, were less inimical to infant life than others. In LATIN AMERICA less than 13 percent of all infants born died each year, while in Asia over 18 percent did. Worst off was AFRICA, particularly sub-Saharan Africa, where infant mortality ranged above 20 percent. Indeed, in some sub-Saharan countries, over a third of all children born perished before they reached five years of age.
Over the next half century, infant mortality dropped dramatically in all these regions, though at different times and rates. In Asia, particularly China, it dropped earliest and fastest, declining from over 19 percent at mid-century to around 4 percent three decades later. Infant mortality also dropped significantly and relatively quickly in Latin America,
TABLE 2
halving by the mid-1980s. Even Africa, which remains the continent most dangerous to infant life, ultimately achieved over a 50 percent decline in the infant death rate. Indeed, at eighty-seven infant deaths per thousand births, the 2000 African infant mortality rate is lower than that in the United States on the eve of World War I.
Contributing significantly to this drop in infant mortality during the second half of the century has been an international movement to improve child health and survival that has been led primarily by two organizations created in the aftermath of World War II: the United Nations Children's Fund (UNICEF) and the World Health Organization (WHO). Through the 1970s, this international effort involved both specific medical and public health interventions aimed at improving nutrition, controlling the incidence of malaria, increasing the availability of immunizations, and promoting in poorer countries the development of health care and public health systems emulating those of wealthier countries. While efforts to purify water supplies generally had positive effects, the overall results of the effort were mixed, and in the early 1980s UNICEF and WHO embarked on a new community-based child survival program which sought to increase immunization and educate community members about proper sanitation, prenatal hygiene, breast-feeding, and the use of a newly developed and simple oral rehydration salt formula for treating infants with acute diarrhea. In combination with continuing efforts to make clean water available, this community-based program seems to have had considerable success. Between the mid-1980s and 2000, infant mortality throughout the world dropped by approximately 30 percent.
Not all infants, of course, have benefited equally from this drop in infant mortality in the less-developed regions. There is considerable variation not only between regions but
TABLE 3
also between different nations in the same region. In sub-Saharan Africa, which each year accounts for over 40 percent of the world's deaths of children less than five, infant mortality in the year 2000 ranged from a low of 58.8 per thousand in Kenya to a high of 130.5 in Malawi. Similarly, in western Asia, Iran had an infant mortality rate of 28.1 while neighboring Afghanistan suffered a rate of 137.5, the highest in the world. Even in the Americas, tremendous variation still exists. Only a relatively narrow stretch of water separates Cuba from Haiti, but an immense gulf exists between their infant mortality rates. In 2000 Cuba had a rate of 7.7 while Haiti had one of 96.3.
As in the past, the causes of infant mortality remain numerous and many: the communicable childhood diseases, diarrheal diseases and gastroenteritis from poor sanitation, pneumonia and other respiratory diseases, an environment infested with the parasites that cause malaria and other debilitating diseases, and the triangle of poverty, malnutrition, and lack of medical supervision that adversely affects the health of pregnant women and leads to gestational problems. Unlike the past, however, relatively effective means of dealing with these causes now exist. The incidence and deadliness of many of the communicable infectious diseases can be controlled by immunization and the use of antibiotics; the incidence of diarrhea and gastritis by improved sanitation, clean water, and use of rehydration therapies; and the incidence of gestational complications by prenatal care programs. All these, however, require resources and the willingness to use them. So long as some countries remain wretchedly impoverished and have governments which cannot or will not apply national resources to saving infants, the modern transformation of infancy from a period characterized by nothing so much as precariousness to one in which survival is almost a certainty will remain incomplete.
See also: Contagious Diseases; Fertility Rates; Obstetrics and Midwifery.
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RICHARD MECKEL