
I think any responsible breeder will not leave a bitch unsupervised in the late part of pregnancy and some puppies losses are inevitable, it is why nature has provided spares so to speak.
Assuming all pups at term are viable whilst still in uterus, it is birth by whatever means that is dangerous.
I know of some breeders overseas that prefer and advocate Elective C sections for all births, as they get all pups out live, and advocate it for all breeds, including my own normally easy whelping breeds.
The same attitude has seen a huge rise in levels of human C sections.
Do we really want to see our dogs eventually unable to give birth naturally???
Now if there was some way of detecting inertia, as opposed to trying to detect the point at which birth should occur in next 24 hours (though useful) won't save puppies that can die within a short time if placentas detach, or there is malpresentation.