Breeding a dog doesn't always produce a litter of puppies. Female dogs go into heat every six months, beginning as young as four months old. Keep a record of breeding attempts during her heat cycle, observations of her health and changes in her behavior and temperament. If your dog has been bred successfully, your veterinarian will be able to verify it by administering a blood test, ultrasound or X-ray.
According to PetMD, your dog may not show any signs of pregnancy for the first three weeks of the nine-week gestation period. She may become more affectionate or demanding of attention, her nipples may swell in size, and her appetite may increase. While these symptoms definitely can be signs of pregnancy, they don't confirm it. Many dogs experience false pregnancy just after their heat cycle. After she has been pregnant for four to five weeks, she will begin to discharge clear mucus from her vaginal opening, which will continue throughout the pregnancy.
Around the time the clear mucus appears (about four weeks into the dog's pregnancy), your veterinarian will be able to detect puppy heartbeats with an ultrasound. During this procedure, your vet will be able to estimate the number of puppies being carried. He may also be able to "palpate" the uterus, or feel the fetuses carefully with his hands. Another option available at 28 days is a blood test, which your vet uses to check for the hormone relaxin, a product of the fertilized and implanted egg. Very small litters (three puppies or fewer) may not register on this test.
Once the pregnancy hits its 60th day, your veterinarian can X-ray your dog's uterus and determine the size of the litter. If the pregnancy has not yet been confirmed, this can also be done with an X-ray. At this time, your vet will be able to tell if your dog will have any complications with the size of her puppies and her birth canal. X-rays should only be performed after the 60th day; earlier X-rays may harm the puppies and their development.
A dog's gestation period normally lasts about 63 days. This length is measured from ovulation, not breeding, and the ovulation and whelping dates can be determined with hormone testing. Expect your dog to eat two to four times more than usual in her last week of pregnancy and first month of lactating. To avoid having your dog choose her own delivery location (in a closet, on a bed), set up a box and give her at least two weeks to become accustomed to sleeping there.
If you think or know that your dog is pregnant, avoid giving her medications throughout her pregnancy and nursing period. In the case of internal and external parasites, it is better to complete her treatment before the puppies are born. If your dog's life is dependent on a medication that isn't usually recommended for pregnant or nursing dogs, your vet may suggest continuing treatment even though it could harm the puppies. Check with her before medicating.