One of the common side affects of the mismate shot is that it causes their body to reject their own bone marrow. Most vets refuse to administer it for more than one accidental mating in the dog's lifetime because the risk to the bitch is so high. Also, doing a spay abort is substantially more risky than a normal spay. The repro vet my dog's breeder uses had to do a C-section on one of her bitches because her uterine horn ruptured and went septic. Even that vet said that if it had been a normal C-section and there was no rupture or infection she would have preferred to let the dog heal up and recover from the pregnancy with all her parts intact before doing a spay.
I personally would prefer death to being deaf and blind.
It's sad how someone can be so intolerable of defects.