Current Trends Infant Mortality in a Rural Health District -
- Georgia
In 1979, the infant mortality rate (IMR) in a south Georgia
health
district, a rural, 16-county area covering 5,943 square miles with
a
population of 249,000, dropped and remained relatively low in 1980,
compared with rates during the preceding 5 years (Figure 4). The
number of births and deaths for infants born 1974-1978 and
1979-1980
were calculated for three birthweight categories: less than
1,500g,
1,500-2,499g, and 2,500g or greater (Table 1). Although infants
with
birth weights greater than 2,500g had the lowest mortality rates,
they
represented 45% of deaths in 1974-1978 and 38% in 1979-1980.
To determine the components of the decline in IMR, a
computerized
registry of linked birth and infant-death certificates, maintained
by
the Georgia Department of Human Resources, was used (1). The
greatest
relative decline in mortality occurred among infants with birth
weights 1,500-2,499g and 2,500g or greater. If
birthweight-specific
neonatal and postneonatal mortality rates* for 1974-1978 had
remained
unchanged, 69 additional deaths would have been expected in
1979-1980
among infants with known birth weights (Table 2). Nearly
two-thirds
(43/69) of the difference between observed and expected deaths
occurred in the 2,500g or greater birthweight category. For
infants
1,500-2,499g and 2,500g or greater, improvements during the
neonatal
and postneonatal periods were approximately equal, while for
smaller
infants, improvement was limited to the neonatal period. When
specific causes of death were examined for infants 2,500g or
greater
(Table 3), decreases in deaths due to infections and birth
trauma/asphyxia/hypoxia contributed the most to the decline in
neonatal deaths, and a decrease in deaths due to infections was the
greatest contributor to the decrease in postneonatal deaths.
The IMR declined from 16.0 to 9.1 for white infants and from
30.4
to 19.1 for infants of other races, while the racial composition of
births remained constant. The percentage of women delivering
infants
at high risk for neonatal death did not decrease (2). Ninety-four
percent of the decline in mortality was attributable to improved
survival within birthweight categories, and 6% to a shift in the
birthweight distribution (3). The decrease in IMR was not
associated
with a parallel increase in admissions to intensive care units for
newborns.
Reported by JT Holloway, Southeast Health Unit, Waycross, S Zaro,
MPH,
Family Health Svcs, RK Sikes, DVM, State Epidemiologist, Georgia
Dept
of Human Resources; Div of Field Services, Epidemiology Program
Office, Div of Reproductive Health, Center for Health Promotion and
Education, Birth Defects Br, Center for Environmental Health, CDC.
Editorial Note
Editorial Note: Most of the recent decline in U.S. neonatal
mortality
has been attributed to improved survival of infants with birth
weights
lower than 2,500g (4,5). In this rural health district, where the
IMR
had been substantially higher than rates in the remainder of
Georgia
and the nation, most of the decline in infant mortality was due to
improved neonatal and postneonatal survival for infants 2,500g or
greater at birth. Within this group, decreases in neonatal
mortality
due to birth trauma/asphyxia/hypoxia may reflect improved
intrapartum
care, and decreases in neonatal and postneonatal deaths due to
infections may reflect improved obstetric and infant care. Changes
in
IMR accompanied efforts to enhance basic prenatal, intrapartum, and
postnatal services for women and infants. In 1975, this health
district began a program providing routine prenatal and infant care
as
a precondition for receiving benefits from a nutrition program for
mothers and infants. By 1979, the program was in effect in all 16
counties and enrolled approximately 30% of the district's pregnant
women. Additionally, physicians in each county were identified who
would offer low-cost obstetric care for high-risk, medically
indigent
women. However, it is not clear why the sharp drop occurred in
1979.
Local and state health officials are conducting further studies to
assess the contribution of participation in the supplemental
nutrition
program and other factors to the decline in infant deaths.
Linking birth and death certificates permits the use of
maternal
and infant characteristics at birth, particularly birth weight, in
describing infant mortality. Analysis of birth weight,
period-of-death, and cause-specific mortality rates forms a basis
for
implementing more appropriate strategies for preventing infant
deaths
and enhancing the evaluation of these programs.
References
McCarthy BJ, Terry J, Rochat RW, Quave S, Tyler CW Jr. The
underregistration of neonatal deaths: Georgia 1947-77. Am J
Public Health 1980;70:977-82.
McCarthy BJ, Schulz KF, Terry JS. Identifying neonatal risk
factors and predicting neonatal deaths in Georgia. Am J Obstet
Gynecol 1982;142:557-62.
Fleiss JL. Statistical methods for rates and proportions. 2nd
ed. New York: Wiley, 1981.
Lee KS, Paneth N, Gartner LM, Pearlman MA, Gruss L. Neonatal
mortality: an analysis of the recent improvement in the United
States. Am J Public Health 1980;70:15-21.
Kleinman JC, Kovar MG, Feldman JJ, Young CA. A comparison of
1960
and 1973-1974 early neonatal mortality in selected states. Am
J
Epidemiol 1978;108:454-69.
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