Dogs are complex creatures and cannot always easily communicate with humans. When it comes time for a dog to breed, humans may have a difficult time telling when a dog is expecting, especially when it is unplanned. Aside from spending money on multiple unnecessary veterinarian visits, owners can tell when a dog is pregnant---or at least when a pregnancy is possible and a vet visit may be needed---by noticing a few early signs in the early weeks of pregnancy.
Depending on the size and breed of dog, pet owners might not be able to tell their dog is pregnant until several weeks into her two-month pregnancy. Most changes will appear 20 days or more after conception, although many more changes are to come in the next 30 to 40-plus days.
Within the few couple of weeks of the pregnancy, many females change their behavior in a number of ways. Some pregnant pets may at first have a decreasing appetite, but eventually gain their appetite back---and then some---to nourish their growing fetus. They also may tire more easily, crave more attention, sleep more or have other abnormal behavior.
Although most of the weight gain isn't seen until a few weeks into the pregnancy, dog owners may notice a pregnant dog's nipples will grow slightly and may change in color in the early stages and more so near the impending birth to prepare for the newborns' nourishment. Owners also may notice some clear vaginal discharge.
Some dogs also may experience other signs of early pregnancy, such as "morning sickness" or vomiting, abnormal sleeping patterns and non-interest in males and some other animals. After several weeks, owners also may be able to feel the pups.
Like with humans, of course, all dogs are different and may experience varying signs of pregnancy at different times. Not all dogs experience vomiting or varying sleeping patterns, and some smaller breeds of dogs may show signs earlier than larger dogs.
The veterinarian field has yet to create an early pregnancy test, but medical treatment is possible after a couple of weeks. Dog owners who feel nearly certain their pet is pregnant should take them in for a veterinarian appointment as soon as possible. The doctor can perform an ultrasound or a blood test to ensure the animal is expecting and provide caring instructions for the master. Regular office visits should follow.