Intrauterine contraception with Nova-T and copper-T-200 during three years

A randomized comparative trial on the clinical performance of two copper-releasing IUDs (Nova-T and Copper-T-200) was performed simultaneously in Denmark, Finland and Sweden. After three years the cumulative pregnancy rate was 1.9 for Nova-T and 5.0 for Copper-T. This difference in efficacy was statistically significant (p less than 0.001). Copper-T had a lower expulsion rate (p less than 0.05) in the total series but not in postmenstrual insertions. Differences between the two devices in other termination rates were not statistically significant. Analysis according to age and parity demonstrated that the pregnancy rate of Nova-T was lower than that of Copper-T in every age and parity group. The pregnancy rate of Nova-T was not effected by age or parity whereas the pregnancy rate and the expulsion rate of Copper-T decreased with increasing age and parity. The removal rate because of infection decreased markedly after the first year of use for both devices. The cumulative rate of removals for infection during the three years of use was not significantly correlated to age and there was no correlation to parity. The continuation rates increased with age and parity. The continuation rates of nulli- and primiparous women were almost identical with both devices and lower than continuation rates of women with 2 or three or more children. Only 11% of the women were lost to follow-up during 36 months. Nova-T had superior effectiveness in preventing undesired pregnancies when compared with Copper-T. The performance of Nova-T is less affected by age and parity then the performance of Copper-T. The silver core in copper wire gives a prolongation of the life-span for Nova-T. For these reasons, Nova-T appears to meet the requirements for an ideal IUD.