PIP: The role of the IUD string in the development of pelvic inflammatory disease (PID) was assessed in a multicenter trial. Subjects were 1st time IUD users with no clinical signs of uterine abnormalities or infection. TCu 200B IUDs with strings were inserted in 150 women; the remaining 150 women were fitted with devices without strings. Clinical follow up was scheduled at 1, 3, 6, and 12 months after insertion or at any time complications occurred. 5 cases of PID were reported during the follow up period: 3 involved women with parity 1 and 2 who received IUDs without strings, and 2 occurred in women of parity 3 or over who received IUDs with strings. These differences were not statistically significant. The 1-year PID rate in the current study was 2.2/100. About 75% of women in both study groups reported purulent discharge at least once during the 1-year follow up period. Urinary problems were reported by 5-10% of particpants. There were no significant differences between women with stringless IUDs and those receiving IUDs with strings in terms of dysmenorrhea, intermenstrual pain, spotting, or pain. Continuation rates at 1 year were 80% for women in both groups of parity 1-2 and 91% for those of parity 3 or more. These results fail to provide any evidence of an increased risk of PID in association with IUD strings.