Intrauterine contraceptive device use and pelvic inflammatory disease

We examined the relationship between use of IUD's and PID, based on 44 women who were admitted to hospitals with first episodes of PID and 259 hospital control subjects. All the women used either IUD's or oral contraceptives. The age-adjusted relative risk for those using IUD's at the time of admission was 6.5 (95% confidence interval, 3.2 to 13.0). The association remained when several variables, and particularly parity, were taken into account. There was a suggestion that users who had had an IUD in place for at least 5 years had a higher risk of PID than did users of shorter duration. The data also suggest that copper-containing IUD's may be safer than other devices.