Sick animals/veterinary services
Allowing a female cat or dog to produce a litter does not have any benefits to the animal. Animals who go through heat cycles and pregnancy are at higher risk for uterine and mammary problems, including mammary cancer, which can be fatal.
There are health risks to the mother during the pregnancy and when giving birth. Proper pre-natal care, emergency care for birth complications, and proper newborn care are expensive and time-consuming.
Learn more about the benefits of spaying and neutering your pet.