Interesting.

It certainly wouldn't hurt to try, seeing as there is a tremendous need for calcium production on the mama, building little skeletons inside her, and fueling the delivered pups with calcium in her milk.

Lack of calcium is also a cause of uterine inertia, and a calcium shot is one of the first things a vet does to assist with the delivery of pups in a difficult birth, since strong contractions rely on optimal calcium levels.

So ... interesting suggestion.

Jack