Tubal infertility in relation to prior induced abortion.

One hundred twenty-seven women who had been given diagnoses of tubal infertility between 1979 and 1981 in King County, Washington, yet previously had been pregnant, were interviewed to determine their prior history of legally induced abortion. Their responses were compared with those of 395 women who conceived a child at the same time the infertile women began their unsuccessful attempt to become pregnant. In making the comparison, we adjusted for the effects of variables that in this population were related both to having an induced abortion and to the occurrence of infertility, i.e., age, number of prior pregnancies, number of sexual partners, cigarette smoking habits, Dalkon Shield (A. H. Robins Company, Richmond, VA) use, and whether the woman worked outside the home. The risk of tubal infertility in women who had had an induced abortion was not increased above that of other women (relative risk, 1.15; 95% confidence interval, 0.70 to 1.89). For women with two or more abortions, the relative risk was 1.29 (95% confidence interval, 0.39 to 4.20). When only the most recent pregnancy was considered, the relative risk was 1.19 (95% confidence interval, 0.72 to 1.97). Our results suggest that legal abortion, as performed during the past decade in the United States, does not carry an excess risk for future tubal infertility.