Infant Mortality

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Infant Mortality

Overview

Infant mortality is defined as the death of an infant between birth and one year of age. Sociologists often look at a nation's infant mortality rate to determine that particular nation's general state of health. International statistics show that the world's industrialized nations have a lower infant mortality rate than that of poorer nations. Infant death may result from a number of causes—stemming from congenital and environmental factors as well as poor diet and medical care—but premature birth is among the most common.

Background

A careful look at individual nations with lower rates often reveals a distinct difference among that nation's ethnic groups; wealthy white babies have a much lower mortality rate than do poor blacks, for instance. Poor mothers have less access to health care and thus have more premature babies, who are then at a higher risk of disease and death. It is every country's goal to improve its infant mortality rates so that every baby born has an equal chance of survival.

Among the countries of the world, the less industrialized nations have high infant mortality rates of about 100 per 1000 births. Western countries that provide good health care programs have lower rates, between 4 to 15 per 1000 births. Japan leads the world with the lowest infant mortality rate of 4 per 1000; Canada and Italy follow with 6 per 1000. In the United States, the rate is about 8.4 per 1000. Poor nations in Asia and Africa have appallingly high rates. For example, Afghanistan's is 147 per 1000, and Sierra Leone's is 133 per 1000. An interesting exception is the impoverished country of Cuba, which has a good infant mortality rate of 9.4 per 1000.

Within Western nations, the rates of infant mortality vary considerably. Different factors explain these rates: economic status and education are among the most important. Women who receive little or no prenatal care are at greater risk of complications during their pregnancies—both to themselves and to their babies. These women have a higher maternal death rate, and their babies have a higher infant mortality rate than mothers who receive adequate medical care during their pregnancies. If the baby does survive, there is more risk of its being premature and/or seriously sick.

A troubling gap exists between black and white infant mortality rates. Even black women who receive prenatal medical care have more premature babies and more low birth weight babies. The black infant mortality rate has been consistently higher than that of whites. Rates for both ethnic groups have declined since 1950, but the rate of white babies has declined almost twice as quickly as that for black babies. In 1950 the infant mortality rate was about 30 per 1000 for white babies, and 50 per 1000 for black babies. Though the figures for both blacks and whites declined dramatically to 15.7 for blacks and 7.4 for whites by 1991, the gap between the two groups had actually widened since 1950 and is not expected to decrease before the year 2010.

A major reason for the drop in infant mortality in recent years is better prenatal care. One part of this care is the use of fetal monitors during pregnancy and labor. Ultrasound helps the physician measure the size and growth of the fetus, and to determine if a problem exists, such as placenta previa, which might necessitate delivery by cesarean section. Monitors also can predict how the fetus will react during labor and if it can survive the stress of a natural delivery. During labor itself, an electrode can be attached to the baby's scalp; if the infant appears to be in distress, the doctor may decide to perform an immediate cesarean section.

Impact

The causes of infant mortality are several, such as certain congenital problems, premature babies and their low birth weights, and sudden infant death syndrome (SIDS). Researchers discovered that babies who sleep on their backs are much less likely to die from SIDS, with the result that the rate of SIDS has dropped by almost 40 percent by 1996. Of all the causes, however, premature births remain the major cause of infant mortality.

The number of premature babies has increased with the higher number of multiple births, which are caused by popular fertility treatments. If a baby is born before 37 weeks of gestation, it is known as a premature baby or a "preemie." These babies have not reached their full birth weight and can weigh as little as 800 grams or about two pounds. A female fetus matures more quickly than a male, so if a premature baby is a girl, she has a better chance of survival than a boy. All preemies have serious problems because their tiny organs are not fully developed. Premature infants need the special care provided by a neonatal intensive care unit where the baby is kept warm, fed, and protected in the proper environment.

An important part of the neonatal intensive care unit (NICU) is the incubator, a special bed or chamber that is kept at a constant temperature of 31° to 32° C (88° to 90° F). This is vital for premature babies because they lack sufficient body fat to keep warm. Incubators have been used since the latter part of the nineteenth century and helped premature babies survive. Today, neonatal intensive care units use both incubators and radiant warmers. Incubators are made of clear plastic and completely enclose the newborn infant, maintaining a certain temperature and level of humidity. A radiant warmer also keeps the baby warm but is completely open on top so that specialists can have easy access to the baby.

Despite the efforts of the neonatal specialists, the tiny baby still faces many health problems. The infant can develop jaundice and have serious respiratory problems. Jaundice causes the skin and eyes to be yellow; it is a common and easily treatable condition resulting from high levels of bilirubin. The premature baby's liver is not yet able to process the bilirubin, so it accumulates in the blood. If the levels are too high, the baby can suffer brain damage. Therefore, the neonatal staff closely monitors a premature baby's bilirubin levels and places the baby under special lighting to help eliminate the bilirubin. In an extreme case of jaundice, the baby may need a blood transfusion.

The most serious problem of the premature infant is breathing. The baby's lungs require a chemical, called surfactant, to function properly. If a premature infant, however, does not have sufficient surfactant in its lungs, the baby develops respiratory distress syndrome. Doctors try to measure the baby's level of surfactant even before it is born.

A test can be performed on the expectant mother if the doctor suspects a premature delivery. This test, an amniocentesis, will determine the level of surfactant in the lungs of the fetus. In an amniocentesis, a needle is injected through the mother's abdomen into the uterus; a sample of the amniotic fluid is taken and checked for surfactant. If the level is low, the doctor will inject the mother with a corticosteroid, which works in about 24 hours.

If the premature baby with respiratory distress syndrome is about to be born, however, there is no time for the injection. After the birth, the infant is placed in the neonatal intensive care unit, and a mechanical ventilator helps the baby breathe. The ventilator, or inhaler, administers the artificial surfactant and helps the baby's tiny lungs function more normally. The nurses continue to monitor the baby's levels of oxygen and carbon dioxide.

Before the NICU was developed in the 1960s, premature babies were treated with an excessive amount of oxygen to help their under-developed lungs. The result is now thought to have caused blindness by making the baby's retina become loosened. Medical researchers agree, however, that oxygen levels only partially explain the damage to the eyes of a premature infant. Babies in the NICU are given regular eye exams to monitor the blood vessels in their eyes. Doctors have turned to laser surgery on preemies in an effort to prevent detached retinas.

Until the late 1960s, hyaline membrane disease was another respiratory problem that was a major cause of death in premature babies. Doctors found that using artificial surfactant helped the infant's tiny lungs function more properly. The last two decades of the twentieth century saw the life expectancy of premature babies increase dramatically, due mainly to the use of surfactant and the NICU. Nevertheless, respiratory distress syndrome remains the major problem for babies born before the 28th week or weighing three pounds or less.

Various factors are responsible for premature delivery. The mother's lifestyle, for example, can definitely affect when her baby is born; smoking, drinking, and a poor diet can all cause her to go into labor early. In addition, there are also physical reasons for premature delivery, such as a mother's illness, infection, or a uterine abnormality. Access to prenatal medical care is also important.

Medical research and the development of the neonatal intensive care unit have allowed more premature infants to survive, but doctors have not yet discovered conclusively how to prevent babies from being born too small or too early. Many babies, about one-tenth of all babies born in the United States, have either a low birth weight or are pre-term. Researchers do know that smoking among pregnant women causes 20 percent of low birth weight babies, a factor that could be prevented. However, they have not yet determined how to prevent the other 80 percent of small babies being born or the specific causes of pre-term births.

The disturbing fact remains that African-American infants are twice as likely to be either pre-term or of low birth weight than either Asian-American or white babies. Until society addresses this discrepancy, the United States will continue to rank far behind many other countries in infant mortality.

M. E. ELGHOBASHI