Multiple induced abortions as risk factor for ectopic pregnancy. A prospective study.

ABSTRACT

PIP: To assess the association between induced abortion and subsequent ectopic pregnancy, 3754 Norwegian women 39 years or younger who had at least one induced abortion at the University Hospital of Trondheim during 1987-92 were followed for histologically confirmed ectopic pregnancies through the end of 1993. In a total of 164,167 woman-months of follow-up, 24 ectopic pregnancies were recorded. No woman had more than one ectopic pregnancy. The overall cumulative incidence of ectopic pregnancy among women with an induced abortion history rose from 3.5 per 1000 women at 1 year to 11.1 per 1000 women at 6 years of follow-up. The adjusted incidence density ratio (aIDR) for women with 2 or more induced abortions was 1.2 (95% confidence interval, 0.5-3.1). No dose-response to ectopic pregnancy was found between 2 consecutive (aIDR, 0.9) and 3 or more consecutive (aIDR, 1.1) abortions compared with the reference group. Ectopic pregnancy after the most recent abortion was more likely to occur among women whose first pregnancy ended as an ectopic one than among those whose first pregnancy resulted in a birth. Although the results of longer-term follow-up of this cohort of Norwegian women have not yet been analyzed, the present findings suggest that induced abortion does not increase the risk of ectopic pregnancy.