Dog Whelping: The Natural Way
In any case, during this second phase of birth, some mothers will vomits, regardless of if they have the stomach full or not; it is not clear why not all of them vomit, although I can depend on their capacity to tolerate birth pains or due to apprehension. During this stage, the contractions are usually every 10 minutes. In this point the puppy is already in the vagina and the pressure that it makes against the dorsal wall stimulates contractions that are always stronger and more continuous. In some cases, you'll notice a more or less evident mucous discharge; however, it is not always recognizable, which is why the bitch at times insistently licks her vulva, which apparently help stimulate contractions and the passing of the puppy toward the vulva.
The first thing that is usually evident, when the puppy reaches the vulva, is the amniotic sac, unless -- of course -- that it has broken along the way, in which case the liquid discharge will have occurred before; the fact that the sac has broken does not mean the puppy is in danger, unless the rupture has occurred a good while before and if it takes a long time for the puppy to reach the point where the vagina dries up, resulting in a more difficult expulsion. You must not ignore that the amniotic membrane is kind of soggy, making it easier for the puppy to pass through, in the same way that if it breaks along the way; it will lubricate it even more.
If everything goes okay, the puppy will appear after two or three strong contractions, that is if the vagina is well lubricated, the vulva is perfectly relaxed and the puppy is protected and contained by the allantoic membranes. If these three circumstances are not met, then there is a chance of birth convocations because the puppy might get stuck halfway along the way, which will make the mother have to push even harder, and will therefore get more tired; what might even happen is that the puppy won't pass through the vulva easily, as we'll see later on.