Will progesterone save the IUD?

In 1971 we began studying pelvic inflammatory disease (PID) in IUD users by examining fallopian tube specimens obtained after elective female sterilization. We studied four groups: 175 nonhormonal-IUD users, 22 Progestasert users, 1,500 non-IUD users and 100 non-IUD users who had had IUDs in the past. We found histologically detectable salpingitis in 49% of the nonhormonal-IUD users, none of whom had symptoms of PID. Culture of 100 specimens from these nonhormonal-IUD specimens proved to be sterile. Viewing the inflammation as predisposing the tissues to bacterial infection would help explain the higher frequency of PID among IUD users than among nonusers. All the Progestasert users lacked histologically detectable salpingitis; the difference was statistically significant (p < 10(-6). This finding suggests that women using progesterone-releasing IUDs have a lower risk of developing PID than do users of other kinds of IUDs.