Further studies of an intravasal copper device in rats

A 1.5 cm long copper wire caused complete inhibition of fertility in male rats when placed properly in the vasal lumen. The contraceptive effectiveness of the device was directly proportional to the surface area of the device and was non-obstructive. The release rate of copper in vivo from a 1.5 cm long wire was 11.6 micrograms/day during the first month and 6.8 micrograms/day over the first 3 months. The contraceptive action of the wire starts about 20 days after insertion. Fertility was regained in 67% of the rats by 90 days after removal of the device. Similar devices of stainless steel and silver did not affect fertility.