Continuous intrauterine copper contraception for 3 years: comparison of replacement at 2 years with continuation of use.

A total of 1245 women had a copper 7 intrauterine contraceptive device (IUD) inserted in 1971-3 were followed up for three years (22 761-5 women months of use). After 24 months 483 women elected to continue with the same copper 7 (continuation group), and 183 had their copper 7 replaced with a new one (replacement group). The subsequent pregnancy and expulsion rates were both significantly lower in the replacement group. The higher pregnancy rate among the women who continued to use their copper 7 device for a third year suggests that although the copper is still there, it is not available for contraceptive action. Replacing the device at 24 months did not seem to cause again the problems that usually occur in the first six months of IUD use.