BIBLIOGRAPHIC INPUT SHEET TEMPORARY Patterns of mortality ...

Chapter XII
Reproductive Patterns
In addition to the multiple causes of infant
mortality, other factors such as maternal
age and infants' birth order have a
direct relationship to the size of infant death
rates. These latter factors have already
been discussed in Chapters VI and X, on
neonatal mortality and congenital anomalies.
One well-known investigation of causal
factors in infant mortality in eight cities of
the United States (Woodbury, 1925) drew
attention to the influence of many biologic
and socioeconomic factors, including age of
mother and parity. In that study death
rates were found to be lowest for inftints of
women 25-29 years old, and to be high for
those of young mothers and of mothers in
the age groups 35-39 years and 40 years and
over. Mortality was excessive in infants of
high birth orders.
Yerushalny et al. (1940) utilized data
from birth and death certificates in Upstate
New York in the period 1936-1938 for studies
of childbirth mortality that likewise
dealt with the important relationship to
birth order and maternal age. Social and
biological factors related to infant mortality
have been studied extensively in England
and Wales by Morris and co-workers (Morris
and Heady, 1955; Heady et al. 1955).
Chase (1961-1963) analyzed matched birth
and death certificates for 1950-1952 in Upstate
New York for thorough study of such
interrelationships.
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Since similar analyses are not known to
be available for countries or cities of Latin
America, one of the goals of the Investigation
was to evaluate these factors in the 15
projects. The reproductive histories of
mothers of deceased children in several projects
revealed that many of the children
were of high birth order and that the losses
through fetal deaths and deaths of those
born alive were large. In this chapter data
on birth order and maternal age are presented
to show how much these factors may
be involved in excessive infant mortality.
Death rates calculated according to
these two factors whenever sufficient bases
were available reveal wide differences in the
Latin American areas.
Birth rates are declining in several areas
and this trend should have a favorable effeet
on infant mortality. Fortunately, data
were available on births by age of mother
and birth order for the Province of Santiago,
and these showed a shift from older to
younger mothers and from high to low birth
orders in a period of rapid decline in the
bir'th rate. Infant mortality has been reduced
by such chages in the pattern of reproduction.
Thus in planning for healthy
infants and for reduction of mortality, these
factors need to be taken into account, along
with the causes of death.
Moreover, the analysis made in this chap­