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Infant Mortality
Reducing Infant Deaths.

Since the NICHD was established, the nation's infant mortality rate has dropped by 70 percent-in part due to the contributions of Institute-sponsored research.[1] The newest advances of NICHD-funded researchers recently identified an exciting and relatively simple means to prevent preterm birth in some cases and uncovered additional threats to infant life and health, for which preventive steps can be taken.

Progesterone Injections Reduce Preterm Delivery. Preterm delivery (before 37 weeks of gestation) is the most important cause of infant mortality and morbidity in the United States. Furthermore, prematurity contributes substantially to racial/ethnic health disparities in infant mortality. It is also very costly. While preterm births account for 12 percent of births in the United States, new estimates show that hospital charges alone for premature/low-birthweight babies reached $13.6 billion in 2001, accounting for one-half of hospital charges for all newborns.[2][3] In addition, preterm babies are more likely to have long-term health problems.

Women whose first baby was preterm are at high risk for subsequent preterm delivery. Until recently, most previously tested strategies to prevent preterm birth in such high-risk women failed to produce effective, reliable results. Early research using progesterone showed promise, but these studies were too small, and the methods and populations were too diverse, to yield conclusive results. Working collaboratively in the NICHD's Maternal-Fetal Medicine Units Network, researchers administered either progesterone (17P) or a placebo to a large group of women who had delivered a previous preterm infant. The 17P-treated women were 30 percent more likely than placebo-treated women to carry their babies to term, and their infants had lower rates of life-threatening complications. African American women benefited as much as white women from the experimental treatment. Furthermore, the researchers found no evidence that 17P caused birth defects or any other problem in the infants of treated mothers. Thus, 17P is a significant breakthrough that holds tremendous promise for reducing preterm birth and life-threatening medical complications in infants of high-risk women. This treatment may also help to reduce the entrenched disparity in birth outcomes for African American infants.

More Babies Survive When Air is Clean. Scientists agree that people who live in areas with polluted air tend to have more health problems. Scientists don't agree, however, as to whether air pollution actually causes the health problems and higher mortality. Areas with higher air pollution also tend to have high population densities, low income levels, and high crime rates, all of which could impact health unfavorably. Further, most previous air pollution research focused on adverse health effects in adults, with little attention paid to children due to the complexities of the issues involved. For instance, children may become ill from exposures that would not affect adults, and children may be more vulnerable to some environmental pollutants than are adults due to their size, growth, and behaviors. An economic recession in 1981-82 provided scientists with a kind of natural laboratory to observe the effects of pollution. The economic slowdown reduced air pollution in selected geographic regions. NICHD-supported researchers were able to demonstrate a causal link between total suspended particulate air pollution and changes in infant death rates. The researchers estimated 100 fewer infant deaths per 100,000 live births occurred during this time of lower air pollution. Most of the decline was observed in very young infants between one day and one month of age. These findings strongly suggest that babies who live in clean air areas have a greater chance of living until their first birthday. The findings also have important implications when determining the cost-benefits of policies aimed at reducing certain types of air pollution and in developing federal, state, and local zoning and air pollution standards. Finally, the findings suggest that obstetrical and pediatric health care providers should more closely monitor their patients in high-risk environments.

Modifiable Risk Factors Associated with the High Rate of Sudden Infant Death Syndrome (SIDS) among Northern Plains Indians. The SIDS rate among American Indians (AIs) is the highest of any population group in the United States and overall is slightly more than double that of whites. The disparity is most acute in the Aberdeen Area of the Indian Health Service (AAIHS), where the SIDS rate is four times greater than that of the U.S. population.[4] The NICHD collaborated with the AAIHS, Centers for Disease Control and Prevention, and the Aberdeen Area Tribal Chairman's Health Board to study infant mortality among AIs and to identify prenatal and postnatal modifiable risk factors that would reduce SIDS risk. The project, which utilized maternal interviews, standardized post mortem procedures, and medical chart reviews, revealed that even one visit by a public health nurse during pregnancy or after birth reduced the infant death rate due to SIDS by one-fifth compared to homes never visited. Furthermore, a mother's binge drinking (five or more drinks at a time) during the first trimester of pregnancy was associated with an eight-fold increased likelihood that her infant would die of SIDS. Finally, infants usually wearing two or more layers of clothing at night, not including the diaper, were six times more likely to die of SIDS. These findings highlight several, key SIDS risk factors that can be targeted in future intervention programs for the AI population.

Encouraging Well-Child Care as a Strategy against Infant Mortality. Despite substantial progress, wide racial disparities in infant mortality remain in the United States. The gap is particularly wide in Washington, D.C., where mortality rates for African American infants in 2000 were 16.1 infant deaths per 1,000 live births-more than double the national rate of 6.9 per 1,000, for all races.[5] A randomized, controlled trial, which was part of the NICHD-funded D.C. Initiative to Reduce Infant Mortality, tested a unique program of educational and supportive services for high-risk mothers and their infants. Nearly all of the mothers in the program were African American, had inadequate or no prenatal care, and had other risk factors including poverty and low educational levels. The program, Pride in Parenting (PIP), provided mothers with information about child health and development and health and social service resources available to them. This information, along with training and social support for the mothers, was provided in home visits, parent-child developmental play groups, and parent support groups.

Unlike similar programs that used nurses for home visits, the PIP program achieved better acceptance by recruiting lay visitors from the mothers' own communities, and by training them extensively in child health and development before they began visiting the mothers. Another unique feature was that program staff neither arranged for nor accompanied mothers to health care and social service sites; instead, mothers were given information on available resources and coached in using services, but were solely responsible for ensuring that their children received the well-child care and immunizations. The program deliberately used lay home visitors to lessen the cultural barriers to health care that account, in part, for disparities in infant mortality and morbidity. Compared to mothers who used standard social services, mothers in the PIP program were more likely to 1) begin well-child care earlier, 2) make more frequent well-child care visits, and 3) complete the scheduled immunizations for their infants. If successfully replicated, this model program could enable minority mothers to seek and use health care for themselves and their children more effectively.



[1] National Center for Health Statistics. New CDC report shows record low infant mortality rate. Available at: http://www.cdc.gov/nchs/data/dvs/lcwk7_2003.pdf (PDF - 1.05 MB) (cited October 2003).

[2] March of Dimes. Fact sheet: Preterm birth. Available at: http://www.marchofdimes.com/california/2265_15490.asp (cited November 2003).

[3] March of Dimes. Hospital Charges for Prematurity-2001 Data, 2003.

[4] CDC. Infant mortality statistics from the 1999 period linked birth/infant death data set. National Vital Statistics Reports 50(4): 21, 2002.

[5] El-Mohandes AE, Katz KS, El Khorazaty, et al. The effect of a parenting education program on the use of preventive pediatric health care services among low-income, minority mothers: A randomized controlled study. Pediatrics 111: 1324-32, 2003.