Pregnancy signs in dogs vary by term of the pregnancy and may include the dogs not being hungry as often and being exhausted during the early stages, notes WebMD. As the pregnancy progresses to the midterm, the dog might get hungry more often and gain weight as a result. During late pregnancy, some symptoms include milk production, a growing abdomen and the puppies moving inside the dog's stomach.
Some other signs that a dog may be pregnant include a change in behavior when the dog is either more or less affectionate than usual, notes PetSource.org. The dog's nipples also grow. When it is time for the dog to give birth, a major sign is restlessness.