Patterns of copper loss--a comparison of the multiload Cu250, TCu-220C and Cu7 IUDs

The rate of copper loss from 329 IUDs (Multiload Cu250, TCu-220C and Cu7) which had been terminated for various reasons after 0.5-46 months in-utero were determined. All 3 IUDs showed a wide scatter of release rates with no significant differences between the ML Cu250 and the Cu7. The TCu-220C showed the highest rates and in contrast to the ML Cu250 and Cu7, the decrease with time was not significant. Its rate of copper loss was significantly higher than the ML Cu250 in the 1st year, but comparable after that. The TCu-220C had a similar rate to the Cu7 in the 1st year and significantly higher rates subsequently. The relevance of these findings to observed pregnancy rates and area of copper on the IUDs is discussed.