受精卵在输卵管中保留3—4天,这对于生理的着床和妊娠是必要的。通过增加输卵管的运动,使受精卵提早地运送进未准备好的子宫内,则将防止着床和妊娠。已证明,前列腺素F_2a(PGF_2a)能增加输卵管的收缩性。在兔的妊娠早期,皮下注射PGF_2a能防止妊娠。由于大剂量的PGF_2a在全身用药时具有明显的毒性,因此,作者试图阐明在排卵后24小时内,给免应用PGF_2a的阴道栓剂作为 Fertilized eggs remain in the fallopian tube 3-4 days, which is necessary for physical implantation and pregnancy. By increasing the fallopian tube movement, so that the fertilized egg delivery into the uterus is not prepared, it will prevent the implantation and pregnancy. Prostaglandin F_2a (PGF_2a) has been shown to increase tubal contractility. In the first trimester of pregnancy in rabbits, subcutaneous injection of PGF2a prevents pregnancy. Since large doses of PGF2a are significantly toxic when administered systemically, the authors attempted to elucidate the feasibility of administering a pessary for parenteral administration of PGF2a within 24 hours after ovulation as a