Performance of the TCu380A and Cu-Fix IUDs in an international randomized trail.

To compare the clinical performance of the TCu380A, the most widely used copper IUD in the world today, and a new frameless device, the Cu-Fix, we report results from a randomized international two-year clinical trial involving 874 parous women followed for an average of fourteen months. Event rates at the end of two years (per 100 women) for pregnancy were 0.0 for the TCu380A and 1.5 for the Cu-Fix. Termination due to expulsion was significantly less for TCu380A as compared with Cu-Fix users (2.0 and 11.4 per hundred women, respectively); other medical reasons for termination (bleeding/pain, pelvic inflammatory disease (PID), and other) did not differ significantly. PID incidence rates at two years were 1.0 per hundred women for the TCu380A and 1.6 for the Cu-Fix (equivalent to 6.0 and 8.3 per 1,000 woman-years, respectively). The net cumulative continuation rates at two years per hundred women were 78.8 for TCu380A, and 71.9 for the Cu-Fix. Both IUDs provide highly effective protection against pregnancy, but the TCu380A has a lower expulsion rate. The low rate of PID indicates that it is an in-frequent occurrence in appropriately selected candidates.