Table
4
Table 4 presents
live births by age of mother, sex and urban/rural residence for as many years as
possible between 1990 and 1998.
Description
of variables: Age is defined as age at last birthday, that is, the difference
between the date of birth and the date of the occurrence of the event, expressed
in completed solar years.
The
urban/rural classification of births is the one provided by each country or
area; it is presumed to be based on the national census definitions of urban
population.
Reliability
of data: Data from civil registers of live births which are reported as
incomplete (less than 90 per cent
completeness) or of unknown completeness are considered unreliable and are set
in italics rather than in roman type.
Table 1 and the technical notes for that table provided more detailed
information on the completeness of live‑birth registration. For more information about the quality
of vital statistics data in general, and the information available on the basis
of the completeness estimates in particular, see section 4.2 of the Technical
Notes.
Limitations:
Statistics on live births by age of mother are subject to the same
qualifications as have been set forth for vital statistics in general and birth
statistics in particular as discussed in section 4 of the Technical
Notes.
The
reliability of the data, an indication of which is described above, is an
important factor in considering the limitations. In addition, some live births
are tabulated by date of registration and not by date of occurrence; these have
been indicated by a (+). Whenever
the lag between the date of occurrence and date of registration is prolonged
and, therefore, a large proportion of the live‑birth registrations are delayed,
birth statistics for any given year may be seriously
affected.
Another
factor which limits international comparability is the practice of some
countries or areas not to include in live‑birth statistics infants who were born
alive but died before the registration of the birth or within the first 24 hours
of life, thus underestimating the total number of live births. Statistics of
this type are footnoted.
Because
these statistics are classified according to age, they are subject to the
limitations with respect to accuracy or age reporting. The factors influencing
inaccurate reporting may be somewhat dissimilar in vital statistics (because of
the differences in the method of taking a census and registering a birth) but,
in general, the same errors can be observed.
The
absence of frequencies in the unknown age group does not necessarily indicate
completely accurate reporting and tabulation of the age item. It is often an indication that the
unknowns have been eliminated by assigning ages to them before tabulation, or by
proportionate distribution after tabulation.
On the other hand, large frequencies in the unknown age category may indicate that a large proportion of the births are illegitimate, the records for which tend to be incomplete in so far as characteristics of the parents are concerned.
Another limitation of
age reporting may result from computing age of mother at birth of child (or at
time of registration) from year of birth rather than from day, month and year of
birth. Information on this factor is given in footnotes when
known.
When
birth statistics are tabulated by date of registration rather than by date of
occurrence, the age of the mother will almost always refer to the date of
registration rather than to the date of birth of the child. Hence, in those
countries or areas where registration of births is delayed, possibly for years,
statistics on births by age of mother should be used with
caution.
In a few countries,
data by age refer to confinements (deliveries) rather than to live births
causing under-estimation in the event of a multiple birth. This practice leads to lack of strict
comparability, both among countries or areas relying on this practice and
between data shown in this table and table 6. A footnote indicates the countries in
which this practice occurs.
The comparability of
data by urban/rural residence is affected by the national definitions of urban
and rural used in tabulating these data.
It is assumed, in the absence of specific information to the contrary,
that the definitions of urban and rural used in connection with the national
population census were also used in the compilation of the vital statistics for
each country or area. However, the
possibility cannot be excluded that, for a given country or area, the same
definitions of urban and rural are not used for both the vital statistics data
and the population census data.
Coverage:
Live births by age of mother are shown for 110 countries or areas. Cross‑classification by sex of child is
shown for 95 countries or areas.
Data are presented by urban/rural residence for 63 countries or
areas.
Earlier
data: Live births by age of mother have been shown for the latest available year
in each issue of the Yearbook. For
information on specific years covered, readers should consult the Index.