Antifertility effects of an intracervical progestational device.

Abstract

To determine the effect of progestagen-impregnated intracervical devices on fertilization implantation and sperm transport silastic devices impregnated with chlormadinone acetate were inserted in one uterine horn of female rabbits. Devices without the progestagen were also placed in rabbits as controls. For fertilization determination the does were mated 10-28 days after insertion of the device and the reproductive tract was examined 48 hours later. Implantation determination was made in 6 does mated 27-48 days after insertion from laparatomies performed 8-15 days after mating. Sperm recovery experiments were performed 4 hours after mating. The rate of hormone absorption from the device in each animal was determined by weight differentials before insertion and after removal. The chlormadinone devices were 100% effective in preventing fertilization in both uterine horns when the hormone absorption rate exceeded 13.7 mcg/kg/day. This contraceptive effectiveness decreased to zero when the absorption rate fell below 7.0 mcg/kg/day. At absorption rates insufficient to prevent fertilization a reduction in the number of implantations was noted. Sperm transport was inhibited in the uterine horns treated with the device but not in the contralateral horn. A preliminary experiment using these chlormadinone-impreganted silastic intracervical devices in women produced highly varied results without any conclusive evidence of contraceptive practicality or effectiveness. The desire for effective contraception with the lowest possible hormonal dose should prompt further research into these devices.