Corrosion of copper in utero.

The influence of corrosion on the copper wire in the Copper T-200 intrauterine device (IUD) was studied in devices which had been in utero for 3 to 52 months. This was done mainly by examining cross-sections of the wires under a light microscope. Corrosion was normally localized to narrow areas and led to breakage and fragmentation of the copper wire. Neither deposits on the wire nor corrosion products prevented the dissolution of the copper. The progress of the corrosion over a given time was determined by comparing the depth of corrosion with the original dimension of the wire. The lifetime of the IUD was evaluated on the basis of the progress of corrosion, the calculated copper release, and the number of cases of wire breakage. It was found that the Copper T-200 could be left in place for up to 45 months.