Pregnancy termination in the bitch and queen

Area of Science:

• Veterinary Medicine
• Reproductive Biology
• Pharmacology

Background:

• Mismate and pregnancy termination are common requests in veterinary practice for dogs and cats.
• Ovariohysterectomy is a definitive solution for owners not intending to breed.
• Pharmacological interventions offer alternatives for preventing or terminating pregnancy in intact animals.

Purpose of the Study:

• To review and evaluate available pharmacological options for mismate and pregnancy termination in dogs and cats.
• To assess drugs based on safety, efficacy, convenience, compliance, and cost.
• To identify the limitations and ideal characteristics of a perfect mismate drug.

Main Methods:

• Review of existing literature on drugs used for estrus suppression, pregnancy prevention, and termination.
• Categorization of drugs based on their mechanism of action (e.g., estrogens, prolactin inhibitors, progesterone blockers).
• Evaluation of drug protocols, including single and combined therapies, and their application during different stages of estrus and pregnancy.

Main Results:

• Estrogens and tamoxifen can prevent pregnancy during estrus.
• Prostaglandins, prolactin inhibitors (cabergoline, bromocriptine, metergoline), and dexamethasone are used to terminate pregnancy.
• Combined protocols and progesterone blockers (mifepristone, aglepristone) are effective but can be expensive.
• Other drugs like isoquinolones and epostane show efficacy but have limited availability.

Conclusions:

• A variety of drugs can be used to prevent or terminate pregnancy in dogs and cats.
• No single drug currently meets all ideal criteria for a mismate treatment.
• Careful consideration of safety, efficacy, cost, and availability is crucial when selecting a treatment option.