Infant Mortality

Definition

The infant mortality rate is the number of deaths of infants under one year of age per 1,000 live births in a given population. In 2002, the United States' infant mortality rate varied widely by race of the mother from 14.3 for infants of black mothers to 5.9 for infants of Hispanic mothers to 5.8 for infants of white mothers. As can be noted, the mortality rate for black infants is more than twice that of white infants. The overall infant mortality rate in 2002 for all races was 7.0 per 1,000 live births, which was a slight increase over the previous year.

Description

Infant mortality rate is one of the key indicators of a nation's health status. When the rate increases, as it did from 2001 to 2002, the factors that precipitated this change need to be assessed and scrutinized. The U.S. infant mortality rate is of great concern because the United States has fallen to the twenty-second nd place among industrialized nations in infant mortality rankings. Therefore, healthcare professionals and the public have stressed the need for better prenatal care, coordination of health services, and the provision of comprehensive maternal-child services.

Infant mortality rates have typically been the highest for the babies of adolescent mothers and lowest for women in their late 20s and early 30s. The rates have also been high for women in their forties and older. In general, infant mortality rates decrease with increasing maternal educational levels. Similarly the infant mortality rate for unmarried mothers is often more than 83 percent higher than the mortality rate for married women. Likewise, the infant mortality rate is characteristically higher for the infants of mothers who smoke than for those of nonsmokers.

The leading cause of infant mortality is congenital malformations, deformations and chromosomal abnormalities with a rate of 20.2 percent. Disorders related to short gestation and low birth weight was the second leading cause of death for all infants at 16.4 percent of all deaths. Sudden infant death syndrome (SIDS) is the third leading cause of infant death. Its incidence decreased by about 9 percent, which it has been doing since 1988. The fourth leading cause of death comes under the heading of newborn affected by maternal complications of pregnancy. This rate actually increased from 2001 to 2002 from 37.2 per 100,000 live births to 42.9 per 100,000 in 2002.

An analysis of the data established that the rise in the infant mortality rate was concentrated in the neonatal period (less than 28 days) and primarily in the first week of life where more than half of all infants' deaths occur. Final birth data for 2002 made it apparent that two key predictors of infant health, the percentage of infants born preterm (less than 37 weeks gestation) and low birth weight (less than 2,500 grams) rose during this time frame. This has been a continuing long-term upward trend. The cesarean section rate for 2002 rose to 26.1, which is the highest ever recorded in the US. The primary cesarean rate was 7 percent higher than the previous year, and the rate of vaginal birth after cesarean (VBAC) experienced a sharp decline. The cesarean rate increase could be due to nonmedical factors as demographics, physician practice patterns, and maternal choice. Other contributing factors may be the use of continuous electronic fetal monitoring and inductions before 41 weeks gestation. Unnecessary interventions can contribute to a rise in cesarean rates. On the other hand, the perinatal mortality rate (the number of late fetal deaths [28 weeks or more gestation] and early neonatal deaths [less than 7 days] per 1,000 live births) remain unchanged.

Common problems

The infant mortality rate increased in the United States in 2002 for the first time since 1958, which indicates a need to examine what factors contributed to this raise. Is there a difference in mortality rates among racial groups? That is obvious—the rate for blacks is 14.2 and the rate for whites is 5.8. Experts associate this difference with the availability of prenatal care to minorities. It is expensive, and over 40 million Americans do not have health insurance. The mother's socioeconomic status is a possible contributing factor because the leading cause of death was related to congenital malformations, which in some cases can be eliminated with appropriate nutritional intake and prenatal vitamins. Lack of prenatal care could also contribute to the fourth largest cause of infant death, which is maternal complications. Many other industrialized countries have a socialized system of health care, which offers universal access to prenatal care and helps lower country-wide infant mortality rates.

Parental concerns

Recent data showed good news for parents of teenagers. The teen birth rate declined by 30 percent over the past decade to a historic low and the rate for black teens was down by more than 40 percent. For young black teens (15 to 17 years) the results were even more striking—the rate was cut in half since 1991. The average age at first birth was 25.1 years in 2002, an all-time high in the United States. Birth rates for women 35–39 (41 births per 1,000 women) and 40–44 (eight per 1,000) were the highest in more than three decades. The rate for women ages 20–24 (104 births per 1,000 women) was on the decline and the rate for those 25–29 was stable, but still the highest of all age groups, at 114 per 1,000 women. In contrast, the rate for teens was 43 per 1,000. In addition, just over one in 10 women smoked during pregnancy in 2002, a decline of 42 percent since 1989.

ORGANIZATIONS

Center of Disease Control and Prevention; 1600 Clifton Rd.; Atlanta, GA 30333.(800)311-3435. Web site: <www.cdc.gov>.

U.S. Department of Health and Human Services. National Center for Health Statistics. Hyattsville, MD 20782. (301) 458-4000.

WEB SITES

Centers for Disease Control. Infant Mortality: Fast Stats. [cited March 6, 2005]. Available online at: <http://www.cdc.gov/nchs/fastasts/infmort.htm>.

Child Trends Databank. Infant, Child, and Youth Mortality. [cited March 6, 2005]. Available online at: <http://www.childtrendsdatabank.org/indicators/63ChildMortality.cfm>.

Linda K. Bennington, MSN, CNS