Copper Levels in Cervical Mucus of Women with Copper-Bearing and Noncopper-Bearing Intrauterine Devices

The copper content of individual cervical mucus samples obtained from women wearing copper-bearing and conventional plastic IUDs was determined, and the values obtained were compared with those of ovulatory noncontraceptive users in the menstrual cycle phases as well as with the duration of use of the IUD. IUD users, with both types of device, showed the same pattern as normal controls, with lowest values of cervical mucus copper observed at midcycle—around the time of ovulation. However, in all phases of the cycle, the copper content of the mucus was higher in copper-IUD users as well as in the plastic (noncopper-bearing) IUD users as compared to normal controls. The mucus samples from copper-IUD users, however, showed the highest mean copper content in all phases of the menstrual cycle. Comparison of copper content with duration of use of the copper device indicated that prolonged use of the device (more than 7 weeks) was associated with a decrease in mucus copper to the levels in women wearing the plastic device.