Ectopic pregnancy and recurrent spontaneous abortion: two associated reproductive failures.

The association between spontaneous abortion and ectopic pregnancy was evaluated in a case-control study conducted on 161 women (cases) with recurrent spontaneous abortions (two or more consecutive spontaneous abortions) and 170 control subjects who delivered normal infants. The risk of ectopic pregnancy in women with a history of recurrent spontaneous abortion was about fourfold that of controls (relative risk adjusted for age and number of pregnancies = 4.3; 95% confidence interval 1.4-14.7). This association was confirmed by comparing the observed number of extrauterine pregnancies in women with recurrent spontaneous abortions with the expected number computed from regional data on the frequency of ectopic pregnancies; the estimated relative risk was 3.7, with a 95% confidence interval of 2.2-7.0. The present report found an association between spontaneous abortions and ectopic pregnancies, suggesting some common risk/etiologic factors for these two reproductive failures.