I don't think I've ever thought of it to the point of needing to come up with a word.. but it'd either be a "cat fetus" or "dog fetus"... or maybe an "unborn puppy" or "unborn kitten". I guess I don't really have an issue with calling the human version an "unborn baby" because you're clarifying that you are aware that what you are talking about isn't actually a baby by qualifying it with "unborn".
My point here is that it's up to the parents. If the parents want it, then by all means, don't abort it - call it a baby - will property to it for all I care (although I think that's ridiculous). If they don't want it - then abort it (unless they'd prefer to have it and give it up for adoption). I just don't think anyone should be telling anyone else what they should be doing with their fetus/unborn baby.
First of all, I want to be clear that while this will sound contradictory, I do not believe deciding to terminate the life of your child (unborn) should be illegal, I do advocate for changing the wording when addressing this with a patient who potentially wants to terminate the baby's life. Yes, that should be up to the parents. But we toe a fine line here because what if someone gives birth to a defective baby, can they terminate the child's life then??
Oh and everyone calls them kitten and puppies whether they're unborn or born, so same thing with babies for me. Humans don't get pregnant with anything but babies last time I checked.