The effect of adding copper onto Lippes Loop IUDs: results from a ten-year study in Yugoslavia

The present study is the first randomized ten-year comparison of the standard, non-medicated Lippes Loop D and the same device with the addition of 200 mm2 of copper in the form of copper sleeves. The devices were randomly inserted immediately after first trimester medical termination of pregnancy. Out of 400 postabortal IUD insertions, 371 were followed for up to ten years. Gross cumulative life-table accidental pregnancy rates after one year of use were 0.56 for the copper-bearing Lippes Loop and 4.63 for the standard Lippes Loop. After two, four and ten years, these rates were 1.24, 2.70 and 3.62 and 6.03, 7.58 and 14.94, respectively (in all comparisons, rates were significantly different at the 0.05 level or lower). At each time interval, expulsion/displacement rates were 4.49, 4.49, 5.23 and 6.32 for the copper-bearing Lippes Loop and 12.61, 13.29, 15.46 and 19.79 for the standard Lippes Loop (rates were significantly different at the 0.01 level or lower). Differences in removal rates for bleeding and/or pain were not significantly different at any of the follow-up intervals. The lower event rates for copper-bearing Lippes Loop D users indicates that the addition of copper to the Lippes Loop IUD may result in better long-term efficacy profiles for this device among postabortal women. The results also suggest that large, medicated IUDs may be more efficacious for women with larger uteri who often experience higher failure rates due to expulsion or displacement of smaller IUDs into the lower uterine segment.