Ectopic pregnancy and prior induced abortion.

ABSTRACT

PIP: A case-control study conducted in 9 US cities as part of the Women's Health Study suggests that prior induced abortion is not associated with a subsequent markedly increased risk of ectopic pregnancy. Study subjects included 462 women hospitalized with an ectopic pregnancy at 16 hospitals in 1976-78. Controls included 2326 women hospitalized during the same period with nongynecologic, medical, or surgical diagnoses. After adjustment for several confounders that are known risk factors for ectopic pregnancy (i.e., race, a history of prior pelvic inflammatory disease, and prior ectopic pregnancy), the relative risk of ectopic pregnancy for women with a history of 1 induced abortion was 1.0 (95% confidence limits, 0.5-1.8). Among women with a history of 2 or more induced abortions, the relative risk of ectopic pregnancy was 0.9 (95% confidence limits, 0.8-1.1). Several earlier studies have suggested a potential increased risk of ectopic pregnancy among women with a history of abortion; however, these studies have generally failed to control for important risk factors, have involved populations from countries that are substantially different demographically from the US, and have included substantial numbers of women whose abortion procedures were illegal.