Termination of Pregnancy ------------------------ General Information An early, unwanted pregnancy is best ended by ovariohysterectomy (spaying). This is an irreversible operation to remove both ovaries and the uterus. The pet is then permanently sterile and will no longer experience the heat cycle. If permanent sterility is not desired, hormone treatments can be given to block implantation of fertilized eggs within the uterus. The eggs then leave the uterus with the uterine secretions, and the pregnancy ends. In a small number of cases, hormonal termination of pregnancy causes some undesirable side effects. Your veterinarian will discuss the risks in this type of treatment. Hormonal treatments are only successful if begun within a few days after mating. Ordinarily such treatment extends the heat period. The dog will continue to attract males, and another mating may occur. The drugs given will usually prevent pregnancy should another mating occur within a few days of the injection. Recommendations: Instructions: