Preliminary testing of the contraceptive collagen sponge.

The results of 3 years of developing the collagen sponge as an intravaginal contraceptive are presented. Postcoital tests were used to evaluate the efficacy of the sponge as a mechanical barrier. Results with the collagen sponge alone were compared to those of the sponge with spermicidal cream or spermicidal solution (acid buffer and zinc) and of spermicidal cream alone. The presence of any motile spermatozoa in the cervical mucus was considered a failure of the barrier method. The collagen sponge alone or with acid and zinc and spermicidal cream alone had failure rates of 22, 20, and 14%, respectively, whereas the collagen sponge with spermicidal cream had a 6% failure rate. The authors conclude that the combination of a mechanical and a chemical barrier is a more effective contraceptive method than a mechanical barrier or chemical agent alone.