THE INCIDENCE OF REPEAT INDUCED-ABORTION - A PROSPECTIVE COHORT STUDY

Background. To measure the cumulative incidence of first and second re peat induced abortion and what differentiates first-time repeaters fro m non-repeaters.Methods. The study population comprised 2 925 women wh o had their first induced abortion at the University Hospital of Trond heim, Norway between January 1, 1987 and December 31, 1991. Repeat ind uced abortion within the study period was measured as a cumulative inc idence of second and third induced abortion. Survival analyses and log istic regression analysis were applied using 'repeater' as the depende nt variable. Results. The cumulative incidence of second induced abort ion was 3.7% at end of first year, 7.1% at end of second year, 9.9% at the end of third year, and 12.3% at four completed years of observati on. The cumulative incidence of third induced abortion was 0.1% at the end of first year, 0.6% at the end of second, 1.3% at the end of thir d and 2.0% at four years of observation. The cumulative incidence of t he third abortion, measured as the time at risk from the second to the third abortion, remained twice that of the cumulative incidence of th e second abortion after one year of observation (p<0.001). At the firs t abortion, variables predicting a risk for repeat induced abortion we re age, occupational status and becoming pregnant as a result of a con traceptive failure. Conclusion. Repeat induced abortion is inevitable. The incidence of repeal induced abortions doubled from the second to the third abortion, indicating that the moral threshold for choosing a n abortion after recognition of an unplanned pregnancy is the first in duced abortion. More detailed studies on the effect of intensified con traceptive counselling programs after the First abortion are needed.