Larger amounts of copper correspond to greater contraceptive effectiveness. Experiments with the ML Cu 375, the IUD with the highest copper content
Van Os, W.A.
Revue Francaise de Gynecologie et d'Obstetrique 80(7): 589-591
1985
ISSN/ISBN: 0035-290X PMID: 4035197 Document Number: 263153
An evaluation of the Cu ML 375 IUD, which has the same structure as the Cu ML 250 but increased copper content, indicates that the greater amount of the copper provides greater protection against accidental pregnancy with no change in the rate of expulsions. The cumulative rates for 1969 insertions of the Cu ML 375 after 12, 24, 36, 48, and 60 months of use respectively were .4, 1.6 2.1, 2.8, and 3.2 for pregnancy; 1.8, 2.3, 2.7, 3.6, and 4.0 for expulsion, 5.9, 10.8, 14.7, 18.5, and 21.2 for removal because of pain and bleeding; .9, 2.3, 3.2, 4.1, and 5.2 for removal because of other medical factors; 5.2, 11.6, 16.0, 19.3, and 22.0 for removal to become pregnant; and 2.7, 5.8, 10.2, 14.0, and 10.4 for removal for other personal reasons. The continuation rates were 85.0, 70.3, 59.5, 51.3, and 44.3 for each of the 5 years. The numbers of cycles covered were 21,762, 39,223, 53,173, 64,567, and 71,818. A simple study of the Cu ML 250 inserted in 877 women gave cumulative rates after 12 and 24 months of 1.2 and 2.0 for accidental pregnancy, 1.3, and 2.1 for expulsion, 5.7 and 10.7 for removal because of pain and bleeding; 3.4 and 3.8 for removal because of other medical factors; 3.0 and 8.5 for removal to become pregnant, and 4.8 and 10.9 for removal for other personal reasons. The continuation rates were 82.7 and 32.3 and the numbers of cycles covered were 9440 and 16,761. The devices were inserted intramenstrually, postpartum, or postabortum in women with no contraindications to IUD use. Another study of the Cu ML 375 2 years later involving 1650 insertions gave cumulative rates of .3 and 1.5 for accidental pregnancy and 1.5 and 2.0 for expulsions. The continuation rates were 85.9 and 71.9. 10,333 and 33,322 cycles were covered respectively. The better contraception offered by the Cu ML 375 appears to result more from the effect of the increased mass of copper than from the increased surface area.