Fertility inhibition by intraoviductal copper beads in rabbits

The effect of intravoiductal copper upon fertility was studied in rabbits. One or five copper spheres (1 Cu or 5 Cu) were inserted in the ampulla of one oviduct and the same number of silver spheres (1 Ag or 5 Ag) were inserted in the contralateral tube. After a recovery period, the animels were mated with fertile males and sacrificed one or 12 days after mating. Partial or total loss of spheres from the oviduct was observed in some animals, more so in the group with 5 beads sacrificed on day 12 of pregnency. The ovulatory response, as judged by the number of corpora lutea, was normal and was not different between sides, or between groups. The rate of recovery of ova and their bution in the genital tract one day after mating was normal, indicating fect of type or number of spheres upon ovum transport at this stage. ber of cleaved ova was significantly reduced by 1 Cu, as compared to by 5 Cu, as compared to 5 Ag or 1 Cu. One or 5 Cu spheres completely implantation in the adjacent uterine horn. Implantation rate in the side bearing 1 Ag was normal, whereas on the side bearing 5 Ag it was significantly reduced. These results show that metallic copper can exert a contraceptive action at the level of the oviduct by interference with the earliest stages of pregnancy. The implications of these findings for the mode of action of copper IUDs are discussed.