Induced abortion. Effects of marital status, age and parity on choice of pregnancy termination.

OBJECTIVE: To study the impact of marital status, age and parity on the decision regarding pregnancy termination over time among pregnant Norwegian women.

DESIGN: National surveillance data of induced abortions and births.

MATERIAL: All women terminating their pregnancies (n = 174,590) as registered in the Abortion File in the Central Bureau of Statistics and all women giving birth (n = 639,551) as registered in the Medical Birth Registry of Norway between January 1, 1979 and December 31, 1990 were eligible for the study. Included in the analysis of pregnancy outcome were records with complete information on marital status, age and parity, which comprise 93.8% (n = 163,826) of all women having had an induced abortion and 99.0% (n = 633,542) of all women giving birth during the time period.

OUTCOME MEASURE: The proportion of pregnancies terminated as induced abortions and the relative risk of pregnant women choosing abortion in strata of marital status, age and parity.

STATISTICAL METHODS: Trend analysis of the proportion of pregnancies terminated as induced abortions in different time periods in categories of marital status, age and parity.

RESULTS AND CONCLUSION: From the first three-year period 1979-81 to the last three-year period 1988-90 there was a decreasing tendency to choose abortion among unmarried pregnant women above 20 years of age and married women with two or more children. In the other strata of marital status, age and parity there were no changes over the time period, except for married women 20-24 years of age which was the only group that showed an increasing abortion tendency over the time period. The prospect of single parenthood was the strongest determinant for choosing abortion independent of age and parity. Within all age groups of married women the abortion tendency increased more with parity than age. Cohabiting women chose abortion significantly more often than married women did. However, the true estimate of choosing abortion among cohabiting women was closer to married women than to single women. In order to find out the importance of other social factors and attitudes in the decision making process regarding pregnancy outcome, adjustments must be made for marital status, age and parity.