Induced abortions and risk of ectopic pregnancy

The relationship between induced abortions and subsequent risk of ectopic pregnancy has been analysed using data from a case-control study conducted in Milan, Italy. The cases were 158 women with a diagnosis of ectopic pregnancy confirmed by laparoscopy or laparotomy, admitted to a network of university and general hospitals. Two control groups were selected. The first one (obstetric controls) included 243 women who gave birth at term (more than 37 weeks gestation) to healthy infants at the same hospitals where the cases had been identified. The second control group (non-obstetric controls) was a random sample of 158 women of comparable age interviewed in the same calendar period, admitted to hospital for a broad spectrum of acute, non-gynaecological or obstetric conditions. A total of 35 out of 158 cases (22%) reported one or more previous induced abortions; the corresponding figures were 29 out of 243 (12%) obstetric controls and 29 out of 158 (18%) non-obstetric ones. The risk of ectopic pregnancy was higher in women reporting induced abortions: the estimated multivariate relative risks (relative risk) for any induced abortions were 2.9 [95%, confidence interval (CI) 1.6-5.3] in comparison with obstetric controls and 2.5 (95% CI 1.2-5.0) in comparison with women admitted to hospital for other conditions. The risk increased with number of induced abortions, being, compared to women with no induced abortion, 13.1 (95% CI 3.2-54.5) and 3.8 (95% CI 1.1-12.7) in women reporting two or more induced abortions when the comparison groups were respectively obstetric and non-obstetric controls. This study shows an increased risk of ectopic pregnancy after induced abortion.(ABSTRACT TRUNCATED AT 250 WORDS)