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

Acta Obstet Gynecol Scand. 1994 Mar;73(3):255-60. doi: 10.3109/00016349409023450.


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.

PIP: Data from the Abortion File of the Central Bureau of Statistics in Norway for 1979-90 were used to examine the relative risks of induced abortion among groups varying by marital status, age, and parity for four 3-year time periods. Between January 1979 and December 1990, 639,551 births were registered and 174,590 pregnancies were terminated by abortion. The mean number of induced abortions in three-year periods increased from 12,800 to 14,600 (14%), and births increased from 50,700 to 58,800 (16%). The two prominent groups having abortions were unmarried women without children aged less than 30 years (40%) and married women with 2 or more children. Declines in abortion occurred among married women with two or more children, from 24% of all abortions in 1979-81 to 15% in 1988-90. Unmarried, pregnant women aged more than 20 years of age experienced a decline in abortion terminations. Unmarried teenage abortions remained stable. Pregnancy terminations increased primarily for married women aged 10-24 years without children. The lowest group with abortions comprised married childless women aged 25-29 years: the reference group. Unmarried women, regardless of age and parity, ended their pregnancies 40-50 times more often than the reference group. Registration of data affected the data by overestimation of abortions among single teenagers by 4% for all time periods. Although abortions increased among unmarried women aged over 20 years, there was still a decline in the proportion of pregnancies terminated by abortion among unmarried women aged over 20 years. Births among cohabiting or unmarried women increased more than the relative number of abortions among unmarried women. Cohabitation increased from 12% in 1977 to 30% in 1988. The suggestion was that the decreasing trend in abortion among pregnant unmarried women might be related to the changes in consensual unions. Data from the 1988 Norway Fertility Survey found that 40% of births were to childless married couples not using contraception, and 5% of abortions occurred among this same group. This means that prevention of unplanned pregnancies would reduce births more than abortions.

MeSH terms

  • Abortion, Induced*
  • Adolescent
  • Adult
  • Cross-Sectional Studies
  • Female
  • Humans
  • Marital Status*
  • Maternal Age
  • Norway
  • Parity
  • Pregnancy
  • Pregnancy Outcome
  • Risk Factors