BIBLIOGRAPHIC INPUT SHEET TEMPORARY Patterns of mortality ...

46 Pattesof Mortality in Childhood
Fia. 25. Neonatal Mortality by Weight at Birth,
United States, 1960.
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the United States in 1960, and Figure 26
shows the distribution of live births in the
same year. The portion of the distribution
of live births that is critical for neonatal
mortality (i.e., those with weights of 2,500
grams or less) has been expanded in the
right-hand section of Figure 26." Crosses
in the figure indicate the percentages of live
births in various weight groups that became
neonatal deaths. As birth weight decreases
the percentages of i)irths resulting in neonatal
deaths increase and would become 100
per cent at some point in the group 1,000
grams or less. Comparability of mortality
depends principally on the completeness of
information on live births and neonatal
deaths in these low-weight groups.
In England and Wales the death rate for
the first day of life (Hirst et al., 1968) re-
* The basic data for the United States used in preparing
these figures are given in Appendix 3.
mained relatively constant from 1950 to
1963, varying from 7.2 to 7.6 per 1,000 live
births. In this same period in the United
States the rate varied from 9.7 to 10.2, and
in the white population from 9.0 to 9.7.
Thus the death rate in the first day of life
was at least 27.6 per cent higher in the
United States. The explanation for this
difference needs to be obtained.
Comparisons with European countries are
because of lack of data by birth
Using percentages from the report
by Hirst et al. (1968), it was found that in
1960 in England and Wales only 0.7 per cent
of the live births were in the weight group
1,500 grams or less, compared with 1.3 per
cent in the United States. Also only 32.0
perL cent of neonatal deaths were in this
weight group, compared with 46.9 per cent
in the United States. What are the reasons
for the differences? Are low-weight babies
born less frequently in England and Wales
than in the United States? Is the WHO
definition applied strictly in both countries?
Research into the frequency of live births
Fio. 26. Percentage Distribution of Live Births
by Birth Weight, United States, 1960.
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