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

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ages of 30 and 34 had the highest birth rates, and women above the age
of 40 did also have many births. After a continuous decline, the age at
birth, has been increasing since 1970. This type of variations in the
timing of births is the reason why cohort fertility is much less variable
than the period fertility.
In chapter 4, the pregnancies and their outcome is the main topic.
The pregnancies have been recorded by means of a form in which all births,
abortions and stillbirths were to be entered. Comparisons with current
population statistics show that the expected numbers of births and stillbirths
have been reported. However, there is a clear underregistration
of induced abortions. At an estimate the figures of the Fertility Survey
as regards induced abortions in 1976 and 1977 are almost 40 per cent lower
than what might have been expected in view of current statistics of
legal induced abortions. The underregistration decreases towards the
early 1970s and is probably of little consequense before 1970. Medical
estimates on the proportion of pregnancies having been terminated by spontaneous
abortion are rather vague. In the Survey, 10 per cent of all
pregnancies were reported to have ended in spontaneous abortion, a figure
which would appear reasonable compared with the estimates which can be
made. There is probably a certain overreporting of spontaneous abortions
and underreporting of induced abortions. It would therefore be natural
to assume that a certain transfer between the two types has occured. In
addition, a number of women may not have wished to mention their induced
abortions and some may not have responded to the survey because they have
had abortions.
Among the women interviewed, 6 482 live births were recorded, i.e.
1.57 per women. A little over 1 per cent of the pregnancies terminated
in a stillbirth and 17 per cent in abortions (a total of 1 315 or 0.32
per woman). A total of 75 per cent had been pregnant. This proportion naturally
varied considerably with age, among the 18 to 19 year-olds, 1 out
of 8 had been pregnant, among the 40 to 44 year-olds, 19 out of 20. 6 per
cent had had 5 or more pregnancies, but as many as 24 per cent of the women
who commenced their first cohabitation prior to 1958 and who were
younger than 45 years in 1977, had had 5 or more pregnancies.
Of the 1 315 abortions, 58 per cent are stated as spontaneous and
41 per cent as induced. There is very little variation in the occurrences
of spontaneous abortions, i.e. their proportion of all pregnancies constitutes
about 10 per cent in most groups. The proportion increases somewhat
with the pregnancy number and with the woman's age at the termination