Oxytocin/Calcium During Whelping
After each puppy is born, the uterus must continue to involute (bunch up, a bit at a time) to bring the next puppy to the birth canal. When a bitch has a small litter, or is taking her sweet time with the whelping, this can take a LONG time. Generally, however, the puppies are safe inside the uterus because their placentas continue to give them oxygen and nutrients.
What breeders and vets often do wrong is that they interpret this interval as labor stopping, and they administer oxytocin. Oxytocin does indeed stimulate contractions, but they are hard contractions as opposed to the gentle slow involution of the uterus.
These hard contractions cause the placenta to separate from the uterine wall, which is usually what happens as the puppy is right at the birth canal and the bitch is having her own hard contractions, but the oxytocin-stimulated contractions happen while the puppy is still far, far from the birth canal. The puppy cannot survive without a placental connection and dies within a few minutes.
That’s why Myra is so adamant that you very, very rarely (if ever) use oxytocin. It’s appropriate only to get a puppy the last couple of inches IF YOU KNOW IT IS THE LAST PUPPY, or to stimulate the uterus to clamp down if the bitch has excessive blood loss or is having trouble expelling placentas.
You use calcium to make sure that the bitch is supported in her OWN contractions; calcium does not do anything artificial to contractions but only allows her own body to contract more efficiently. Even on this list it’s often said that calcium strengthens contractions – that’s a bit of a misconception. Calcium doesn’t do anything except make the bitch’s body work as well as it can; the contractions will never be harder than her own body can produce (unlike oxytocin-stimulated contractions, which are artificially hard).
So calcium can prevent or address uterine inertia that is the result of calcium deficiency; that’s a very common cause of inertia and so it often helps. However, if there are other underlying causes for the inertia, calcium will not help and you’re looking at a section. The good thing about not using anything but calcium is that when you DO have to do a section, you’re pulling out live puppies instead of dead ones that the oxytocin killed.
If you give oral calcium, you don’t have to worry about monitoring the heart. IV calcium should only be done by a vet.