Abdominal Enlargement

One of the most obvious signs of pregnancy in dogs is an expanding belly. Weight gain becomes obvious in the second half of pregnancy, and the abdomen may feel firmer during the last couple of weeks. It is around this time that it becomes possible to see the outline or movement of pups, especially when mama dog is carrying a large litter. Be gentle when feeling for little ones, though; excessive poking and prodding can cause discomfort or even miscarriage, according to the "Dog Owner's Home Veterinary Handbook." Ask your veterinarian for tips on safely feeling for puppies.

Behavioral Changes

Pregnant dogs exhibit numerous behavioral changes during pregnancy. Some may be obvious, while others are likely subtle and only detectable if you're actively looking for them. If your pooch becomes more or less affectionate than usual, experiences changes in appetite, or seems tired and out of sorts, she may be pregnant. Changes in behavior and activity level occur due to a combination of instinct and hormonal changes. Nesting behavior and restlessness typically occur a few days before delivery.

Breast and Nipple Changes

Your dog's nipples are normally small and the area beneath them is flat. Once she becomes pregnant, this mammary tissue will grow and swell in preparation for feeding her pups. Milk production begins as delivery draws near. Colostrum, the first milk, may begin leaking from your dog's nipples during late pregnancy.

Veterinarian Exam and Testing

Even if you're certain your dog is showing signs of pregnancy, it's still a good idea to have your veterinarian check her out. An ultrasound of her abdomen can detect many pregnancy problems and show the number of unborn pups. It will also rule out a false pregnancy. Your vet can perform an ultrasound as early as a few weeks into the pregnancy and the test is safe and effective. Blood tests are also available to confirm or rule out pregnancy in dogs.