What are the main situations of irregularities that can occur during childbirth in dogs and cats?

The main situations of irregularities that can occur during childbirth in dogs and cats are excessively long gestations, uterine inertia, ineffective expulsion efforts, too long intervals between expulsions, incorrect presentations of the fetus, and tetany or agalactia in the mother.
In the case of uterine inertia, the mother does not show obvious signs of contractions, and in the case of ineffective expulsion efforts, the mother continues to push for more than half an hour without being able to expel the fetus.
In the case of incorrect presentations of the fetus, the fetus may adopt a wrong posture during delivery, and in the case of tetany or agalactia in the mother, it is necessary to establish artificial feeding for the newborns and an appropriate treatment for the mother.