A Literature Review of the Effects of Copper Intrauterine Devices on Blood Copper Levels in Humans.

Copper is a trace mineral that is essential to human health but can be harmful in excess. Since the introduction of copper-containing intrauterine devices in the 1970s, their possible relationship to abnormal/toxic blood copper levels has been researched. Here, we summarize and interpret 12 studies that evaluate blood copper levels in users of copper-containing intrauterine devices. The data are inconclusive, with the results of eight studies indicating no increase in blood copper levels with use and the results of four studies showing significant increases in blood copper levels with use. Investigators in all studies reviewed appear to have evaluated for total copper rather than free copper (the form of copper that is toxic), which raises questions about the clinical significance of all research on this subject to date.