Induced abortions and births. Changes in maternal age and parity in six counties, Norway, 1972-1981.

During the 1970s the abortion law changed twice in Norway. As of 1976 induced abortion was accepted on social indications, while abortion on womens' demand was introduced in 1979. This study presents age-specific abortion- and birth rates as well as age- and parity-specific abortion ratio from 1972-1981. From 1972 to 1974 the number of induced abortions increased. Since then the general abortion rate has decreased. For all parity groups the number of pregnancies terminated by induced abortion increased during the first 3 years of the study. While nulliparous women showed a continuous increase in the abortion ratio throughout the study period, the abortion ratio for parous women has been relatively stable since 1975. Through the use of induced abortion nulliparous mothers postpone the birth of their first child. Therefore induced abortion contributes to an increasing maternal age at first child birth. The present study can support the hypothesis that multiparous women, among other means, have used induced abortion to establish the 2-child family norm during the 1970s.