Invasive cervical cancer and intrauterine device use.

Although the hypothesis that intrauterine device (IUD) use might promote cervical cancer has been considered since the introduction of IUDs in the early 1900s, previous studies are inconclusive. Data collected in interviews with 481 invasive cervical cancer cases and 801 general population controls from Birmingham, Chicago, Denver, Miami and Philadelphia were used to address this issue. These data were analysed to determine the relationship between IUD use and the risk of cervical cancer, with consideration of the type of IUD (copper and inert) and duration of use. A non-significant reduced risk of cervical cancer was associated with copper IUD use, indicated by an adjusted odds ratio (OR) of 0.6 (95% Cl: 0.3-1.2), but virtually no effect was found for inert IUD use (OR = 1.1, 95% Cl: 0.9-1.7). Decreased risk with increased duration of copper IUD use supports a possible protective effect of copper IUD use on the development of invasive cervical cancer.