How do you tell if a dog is pregnant?

Your dog can have a blood test at around 28 to 30 days gestation. Your vet will try to determine pregnancy by checking for a hormone called relaxin. However, if your dog is pregnant with a small litter (one or two puppies), the blood test may result in a false negative

During the first 2-3 weeks you will not see any physical signs. Look at your dog's nipples, for if it is pink, that may be an indication. Be sure to observe your dog's body and it's weight.