49. Fruktbarhet blant norske kvinner: Resultater fra ... - SSB

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As was the case for the first birth, it seems that the age of the
women at their second birth has changed very little. However, it is only
women born 1933 - 1947 who, up to the interview had a sufficient
number of second births to make estimation of trends possible. Among all
women born 1933 - 1947, 50 per cent had had at least two births by the
time they reached 26-27 years.
Usually, the second child comes a fairly short time after the first
one. Among women 30-44 years of age with at least two births, nearly 50
per cent have had the second child within 2 1/2 years after the first. Only
1/4 of the women had 4 years or more between their two first births.
The time distance between second and third birth is slightly longer
than the one between the first two births. It is not so usual to have second
and third birth very close together, and more than 1/3 of the women
had at least 4 years between these two births.
The length of the periods between births are dependent upon the
distance between marriage and the first birth. Those who got their first
child within the first year of the marriage, have shorter intervals between
the three first births than women with first birth 1-3 years after marriage.
The length of the reproductive period (measured as number of years
between the first and the last birth up to the time of the interview) has
been calculated for women 35-44 years of age who have at least two live
births. One quarter of these women have a reproductive period of less
than 4 years, 29 per cent have 4 to 6 years between first and last birth,
22 per cent have between 7 and 9 years and for one quarter of the women,
their reproductive period was at least 10 years. The length of the reproductive
period will of course be strongly dependent upon the number of
live births. Among those with two children, the majority have had their
births within less than 4 years. If a woman has had three births, a reproductive
period of 4 to 9 years is most common, whereas women with more
than three births usually have had them over a time span of 10 years or
more.
Only women older than 34 years of age could be expected to have
completed their reproductive period at the time of the interview. In the
absence of completed birth histories, we have compared the number of children
at given ages for women belonging to different birth cohorts. Differences
between the cohorts may be the result of changes in the timing
of births as well as changes in the total fertility.