The most obvious signs of a dog prenatally are shortness of breath, restlessness, swelling of the reproductive organs and mucus leakage. Dogs will also experience labor pains before giving birth, so they will be more anxious. When a dog shows prenatal signs, it will give birth in about 3 to 10 hours. After discovery, it is best to bring the dog into the prepared delivery room or kennel, and wait quietly for the dog to give birth. If any abnormality is found, call it immediately. Send the dog to the hospital to avoid dystocia.