What causes the uterus to become refractory to oxytocin?

How is secondary uterine inertia different from regular labor?

What physical signs indicate puppies are ready to be born?

Why the Uterus Becomes Refractory to Oxytocin A dog’s uterus becomes refractory—meaning it completely stops responding to the medication—simply after it has been given a few doses of oxytocin. Because of this limitation, veterinarians typically administer a maximum of only two doses spaced 20 minutes apart; if labor does not progress, a cesarean section is required.

Secondary Uterine Inertia vs. Regular Labor While regular active labor involves continuous contractions to deliver puppies, secondary uterine inertia occurs when a dog experiences a period of apparently normal labor that suddenly ceases. A veterinarian makes this diagnosis when labor stops despite there being no physical obstructions or problems involving the birth canal, such as a stuck puppy.

Physical Signs Puppies Are Ready to Be Born Veterinarians can observe specific physical signs of fetal development using an ultrasound during the final 48 hours of pregnancy to confirm the puppies are fully developed and ready for birth. These signs include:

• The internal structure of the puppies’ kidneys becoming visible.

• The puppies’ intestinal tracts beginning normal peristaltic movements.

Additionally, a primary physical sign in the mother that she is ready to give birth within 12 to 24 hours is a drop in her rectal temperature. This drop is usually 2 to 3°F lower than her baseline, typically falling below 99°F (around 97 to 98°F).