Panting or breathing heavily and rapidly in a pregnant dog is a sign that labor contractions have begun. Dogs normally pant when in pain. (See Reference 2) Pregnant dogs in labor will also lick their vulvas and try to find a dark, quiet spot to whelp (give birth.) (See Reference 1)
Many dogs can whelp naturally, but some breeds with narrow hips and large heads like bulldogs cannot whelp naturally. The puppies' heads are too big to fit through the birth canal. Panting is a sign the pregnant dog of such breeds needs to go to the vet for a Cesarean section. (See Reference 3)
The first sign of labor can last from 6 to 12 hours, although contractions have not started so the dog may not pant. Panting starts when the contractions begin. The first puppy should appear in 30 minutes. If not, call a vet. (See Reference 1)
Pregnant dogs may not pant while whelping every puppy in the litter, but they often pant when strong contractions hit. Dogs can take up to two hours in between whelping puppies in the same litter. If a dog actively goes into labor with panting and then is too exhausted to continue, she may have uterine inertia and needs veterinary assistance immediately. (See Reference 4)
Rena Sherwood is a writer and Peter Gabriel fan who has lived in America and England. She has studied animals most of her life through direct observation and maintaining a personal library about pets. She has earned an associate degree in liberal arts from Delaware County Community College and a bachelor's degree in English from Millersville University.