IUDs and PID: a comparative trial of strings versus stringless devices.

An international multicentered clinical trial was designed to determine the possible role of intrauterine device (IUD) marker strings in the etiology of pelvic inflammatory disease (PID). A total of 1265 women were admitted and randomly allocated to receive either a standard TCu200 IUD or a TCu200 IUD without marker strings. These patients were followed-up through 12 months postinsertion. No statistically significant differences were found between the two groups of IUD users with respect to the incidence of PID or other types of infection or inflammation. The 12-month life table termination rates and overall continuation rates were also similar for users of the respective devices, with the exception of removal rates for bleeding/pain, which were significantly higher in the strings group than in the stringless group. However, the number of bleeding/pain complaints ever reported during the study were not statistically different in the two study groups. The study results indicate that the IUD string does not play an important role in the etiology of PID associated with the use of IUDs.