Infant mortality is the name given to the number of infant deaths in the first 12 months of life per every 1,000 births. In 1996, the primary causes of infant mortality were congenital disorders related to immaturity (premature births), low birth weight (LBW)(infants weighing less than 5lb. 9oz or 2,500 grams). Some of the most common reasons for infant mortality due to LBW includerespiratory distress syndrome, which may involve atelectasis (collapsed lungor lungs), hypoxemia (low oxygen absorption), and high carbon dioxide levels.Sudden Infant Death Syndrome (SIDS), and lack of the essentials of life, i.e., adequate food, warmth, shelter, and water, all contribute to infant mortality. In a typical population, the mortality rate is higher among male infantsthan female infants, mainly because male births are also higher.
More than 60% of infant deaths occur within the first 27 days after birth, known formally as the neonatal period, and are most often attributed to premature birth (before the 30th week of gestation), LBW, or serious birth defects.Infant mortality rates are one of the most tracked health care statistics inthe world and are used as socioeconomic indicators because the rate of infantdeaths is lower in developed and industrialized countries, city areas with ahigher density of whites and higher income/education brackets, and is decreasing in areas where governmental and public health and awareness campaigns are being implemented. Even though the infant mortality rate was 6.33 of every1,000 births in the United States in 1999 (compared to Pakistan at 91.86/1000), the U.S. still has one of the highest infant mortality rates among all developed countries, ranking 25th in the world.
History and Decline of Infant Mortality in the United States
In 1900, approximately 100 infants died for every 1,000 births and from six to nine women died from pregnancy-related causes. Between 1915 and 1997, infant mortality declined more than 90%, and maternal deaths by 99%. This was alldue to the rapid improvement in standards of living, medical science, sanitation, water purification, and nutrition, combined with higher education and economic conditions, development of pasteurization for milk, vaccinations against childhood infectious diseases, more options in contraception, smaller families, and longer periods between the birth of siblings.
Through the 1930s, public health, welfare, and the medical profession all worked together to reduce the infant mortality rate. The Children's Bureau, a governmental agency established in 1912 and extremely influential through 1946,was highly effective in initiating extensive welfare medical services to pregnant women and babies. This initiative included pre-and postnatal home visits by health care professionals, and ultimately expanded to include pre-and postnatal education, guidance, and care for expectant mothers.
With the development of sulfur-containing (anti-microbial) drugs in 1937, penicillin in the 1940s, and re-hydration and improved blood transfusion methods, by 1949 infant deaths declined 52%. By this time, it was noted that the largest decrease in mortality was among the postnatal infants (those babies older than 28 days), and the highest infant mortality rates were among "high-risk" neonatal (27-day-old or younger), those born prematurely or of LBW.
During the 1950s and 1960s, attention once again focused on the young neonates, with attempts to make health care more accessible to low-income populations and to developing medical technology and intensive care units for the at-risk newborns. With the introduction of Medicaid in the 1960s, post neonatal mortality dropped once again, due to advances in medical technology and concerted efforts to identify low-income populations/regions to provide those pregnant women and infants with greater access to health care resources.
The slight decline of infant mortality in the late 1980s was probably due topulmonary surfactants developed to prevent respiratory distress syndrome. Thenext significant decline during the early to mid 1990s was due primarily toan almost 50% reduction in SIDS. Continuing advances in prenatal diagnostic technology and selective pregnancy termination; surgery on infants while stillin the womb to help correct structural and organ defects; and the discoverythat adding folic acid to the diet of women of childbearing age to prevent neural tube defects, have all improved the rate of infant mortality during thelate 1990s.
Remaining Risk Factors
Currently in the United States, the greatest risk factors for LWBs include smoking while pregnant, and teen pregnancies. More than 12% of smokers give birth to LBW babies, and LBW is the primary cause of neonatal infant mortality.Also, the U.S. has a higher teen pregnancy rate than almost any other developed country, and 95% of these pregnancies are reported to be accidental. (In fact, more than 52% of all pregnancies in the U.S. are reported to be accidental.) According to a report by "Healthy Start" in Pittsburgh, Pennsylvania, approximately one in eight babies born to teens will be LBW, and more than one in every five babies who die in the U.S. are to teen mothers.
Increasing the risk of infant mortality in teen births is the fact that teensare least likely to access medical care during the first trimester of pregnancy, during the remainder of their pregnancy, and after their baby is born. Teenage women using drugs and/or alcohol are more likely to experience pregnancy outside of marriage than teen women who do not use drugs and alcohol.
Race and ethnicity is also a risk factor. Since 1990, the infant mortality rate in the U.S. has dropped almost 22%. However, according to the U.S. Department of Heath and Human Services, although 1998 saw a significant reduction inmortality rates from HIV/AIDS, murders and violent crimes, as well as a decline in teen births, the infant mortality rate remained the same as in 1997 (7.2/1,000). There was actually an increase in LBW babies in 1998, accounting for 7.6% of all births compared with 7.5% the previous year. While this increase was noted only among the non-Hispanic white population, LBWs among African-American women remained twice as high as Hispanic and white women. An African-American women whose household income is less than $10,000 annually is almost twice as likely to give birth to a LBW infant, and four times more likelythan a white woman with a household income of more than $40,000 annually. Twice as many African-American babies compared to white American babies are likely to die before the age of one, and the American Indian/Alaska native population historically experienced a 70% higher infant mortality rate than white Americans.
Infant Mortality Rates as Socioeconomic Indicators
Infant mortality rates are good indicators of discrepancies in the quality ofeducation and medical care available to different socioeconomic or ethnic populations in a country, state, or even a city. Globally, as of 1999, the infant mortality rate was about 80 infants per 1,000 (8%). In developed countries, the rate was below 10 per 1,000 (1%) and in undeveloped nations it neared 200 per 1,000 (20%). Industrialized countries such as France have lower infantmortality rates (5.62/1,000) than less developed countries such as Kenya (59.07/1,000). This is generally due to greater access to advanced medical technology, adequate sanitation, contraception, good nutrition for prenatal and postnatal care, and educational and informational awareness programs in developed nations. The lowest infant mortality rates in the world are in Finland (3.80/1,000), Sweden (3.91/1,000), and Switzerland (4.87/1,000).
On a city/area based level, according to a "Healthy Start" study conducted inPittsburgh, Pennsylvania, "...poor pregnancy outcomes in high risk communities were associated with a broad range of factors including underemployment, under-education, and economic priorities; social factors including single parenting and teenage pregnancy; and medical factors which include late utilization and under-utilization of prenatal and postnatal services."
Prevention of Infant Mortality
In a fact sheet on preventing infant mortality, the U.S. Department of Healthand Human Services (HHS) states that "...early and continuous prenatal carehelps prevent low birth weight and identify conditions and behavioral factorsthat often cause or aggravate low birth weight, such as smoking, drug and alcohol abuse, inadequate weight gain during pregnancy, and repeat pregnancy insix months or less." In an effort to help prevent infant mortality in the U.S., HHS has implemented a number of initiatives and programs during the 1990s. These include:
- "Early Head Start" program designed to expand medicalservices and early childhood development education and training to low-income pregnant women and families.
- Far-reaching childhood immunization programs to combat infectious childhood diseases. (One hundred years ago, almost 50% of all infant mortality was caused by infectious disease and malnutrition. Malnutrition is still a major cause-particularly in underdeveloped nations, while infectious diseases have been virtually eradicated through global immunization programs.)
- Comprehensive primary health, mental health, and dental health services for low-income and homeless populations through school-based programs.
- A 1996 law to increase affordability of health care and insurance programs to low-income families and to protect families whenthe insured is "between jobs." (Approximately one in 10 Americans change jobsannually, are self-employed, or have pre-existing medical conditions that often limit their ability to get insurance coverage).
- The 1997 law providing the largest increase in government funding ($24 billion) to provide health insurance for low-income children since Medicaid was established in 1965.
Also, in 1992, the Public Health Services recommended the daily consumption of 400 micrograms (mcg) of folic acid by women of childbearing age, reducing by up to 50% the risk of giving birth to a baby with neural tube defect (spinabifida or anencephaly). This serious birth defect affects 4,000 infants eachyear.
Ongoing advances in medical knowledge and treatment continues to improve survival rates of LBW infants. Corticosteroids used during premature labor increase the survival rate of premature infants and help prevent respiratory distress syndrome and internal infant hemorrhaging. Also, simply by accurately diagnosing common bacterial vaginosis in pregnant women and treating it with thecorrect antibiotics reduces the patient's risk of premature delivery.
Perhaps one of the most significant reasons for lower infant mortality ratesin the U.S. in the 1990s has been the "Back to Sleep" campaign initiated by the National Institutes of Health's National Institute of Child Health and Human Development, in collaboration with many other agencies. This combined public health and awareness effort has brought about as much as a 50% reduction in SIDS related deaths through educational programs that recommend infants beplaced only on their sides or backs to sleep and not on their stomachs.
Reduced Infant Mortality in Certain Native American and Alaskan Tribes
A 1999 article from the Ancorage Daily News referred to a federal study on Indian and Alaskan tribes in Washington, Oregon, and Idaho in which theinfant mortality rate dropped drastically during the 1980s and 1990s. When tribe members noticed fewer babies were dying, the director of the Northwest Tribal Epidemiology Center at the Northwest Portland Area Indian Health Board initiated a study to investigate the reports. The study showed the infant death rate decreased from 20/1,000 deaths in the mid to late 1980s to less than 8/1,000 in the late 1990s, bringing it to approximately the national average.
Although the reason for the decrease had not been clearly identified at the writing of the article, several factors are suspected to be involved. They include the provision of special care for high-risk mothers, an expansion of state-provided medical care in Washington for pregnant women and their newborn infants, and technological advances in assisting respiration of premature/LBWinfants. The study noted that almost half the decline was due to a reductionin the rate of SIDS. This success was credited to educational programs encouraging parents to refrain from smoking tobacco around their infants, and placing infants on their back or side to sleep. A longtime pediatric nurse practitioner for one of the tribes is quoted in the article as saying: "They were onthe right track back in the traditional days, putting them on baby boards,"referring the practice of wrapping infants securely on their backs on carrying boards.
Remaining Challenges Facing Infant Mortality Reduction in the United States
In an October, 1999 report, "Achievements in Public Health, 1900-1999: Healthier Mothers and Babies," researchers indicate "the greatest [challenge] is the persistent difference in maternal and infant health among various racial/ethnic groups, particularly between black and white women and infants." For example, one study comparing infant health in a low-income, minority community in East Harlem, and a high-income area from Kips Bay to Yorkville, all in NewYork City, found that pregnant women in the high-income area had six times the prenatal care and a three to four times lower rate of LBW babies than pregnant women in the low-income region. However, the study also states that, evenwhen income and educational levels are more equal, a large disparity in infant mortality rates still remain-that black college-educated, middle income bracket women still experience twice the number of LBW babies as their white peer group. This study also notes that, although infant mortality in the U.S. is among the highest in industrial nations, once babies enter the health caresystem, their chances of survival increase drastically due to medical technology and physician expertise.
A similar observation is noted in other reports-that the reduction in neonatal infant mortality is not due to a drastic reduction in LBW infants, but to improvements in methods to keep them alive. The challenge now remains to helpprevent LBW in the first place. Almost half the pregnancies in the U.S. are unintended, and three-fourths of those are among women younger than 20-a high-risk group for LBW babies. Added to the risk in unintended pregnancies are lifestyle choice factors such as poor nutrition, smoking, alcohol and drug use,unsafe sex practices, and low intake of folic acid which are more prevalentamong this group of women. All of these issues remain a major challenge in reducing the rate of infant mortality.
Future studies to develop effective strategies to further reduce infant mortality include research not only into biological factors, but the effects of stress, psychological, environmental, and socioeconomic influences experiencedby a woman while she is pregnant. Researchers are investigating fetal programming--the way maternal stress, nutrition, health, or illness experienced during pregnancy--affects offspring from infancy through childhood and into adulthood.
It seems the most challenging obstacle in lowering infant mortality--not justin the U.S. but worldwide--is providing adequate pre and postnatal healthcare, education, and nutrition to women who otherwise have little or no access to these types of services to help them understand pregnancy and infant care.