Comparison of segmented polyether urethane with polyethylene IUDs in rabbits.

A segmented polyether urethane IUD was compared with a polyethylene IUD in rabbits. The contraceptive efficacy of urethane IUDs was excellent. Moreover, the purulent slippery deposit present with the polyethylene IUDs and observed by Davis et al. (1) was absent. Our studies indicate that the polyether urethane IUDs have a high degree of antifertility activity in rabbits and these IUDs have reduced inflammatory response, based on leucocytic infiltration and tissue debris in the uterine lumen. It is suggested that polyether urethane IUDs not requiring copper or other medication can be designed for high contraceptive efficacy, intrauterine compatibility and with the necessary rigidity for proper uterine retention in humans.