Reduction of fertility of mice by the intrauterine injection of prostaglandin antagonists.

The intrauterine injection of 7-oxa-13-prostynoic acid, 18,18,20-trimethyl PGE-2, and meclofenamic acid in mice at the expected times of implantation significantly reduced the number of implantation sites. Indomethacin was ineffective possibly because it was exposed to high pH during the preparation of the solutions for injection. It is suggested that these prostaglandin antagonists exert their antifertility action at multiple sites involving both the embryo and mother.