The only truly reliable way to determine if a dog is pregnant is a trip to a veterinarian. Some dogs can mimic signs of pregnancy even when they are not, so a trained professional needs to rule out that possibility. Vets can physically examine the prospective mom and then perform several tests to confirm the diagnosis. Ultrasounds are non invasive and used to detect fetal heart beats, but x rays are recommended later in the pregnancy to determine size of the litter through fetal skeleton imagining. Yet even before the vet visit, an owner may see several signs of pregnancy.
Change in Appetite
Dogs don’t really experience morning sickness like humans, but a loss of appetite can be one of the first symptoms of pregnancy. Not all dogs will eat less than normal (some will eat more), and those that do have decreased appetite will make up for it at about 3 weeks into the pregnancy by eating more.
Decrease in Activity
A change in hormone levels can produce lethargy, and the dog may sleep more than usual. This early sign of detecting pregnancy can be especially evident in dogs that are usually very active.
The expectant dog will get larger nipples at about 3 weeks into the pregnancy. The tissue under the nipple will become slightly engorged in preparation for milk production, raising the usually small, flat nipples. Later in the pregnancy, colostrums can be expressed and even leak out as the delivery time draws closer.
Pregnant dogs can have very definite changes in behavior either for better or worse. They can be more affectionate and will require more company, or suddenly prefer to be left alone and find ways to seclude themselves. This behavior can intensify as the pregnancy progresses, culminating in the dog exhibiting “nesting” behaviors characterized by shredding paper or digging in bedding.
About a month into a pregnancy, the dog‘s abdomen will thicken and feel firm, rather than soft when palpitated. An experienced vet will very easily feel this thickening about 20 days into the pregnancy. Later, the weight gain will be very apparent and the movement of the puppies can even be felt. The breed of dog and size of the litter will determine exactly how big the dog gets as the pregnancy progresses. Smaller dogs will usually show more, and can actually have their stomachs drag on the ground in some cases.