There are various ways to determine if a dog is pregnant. Depending on the stage of pregnancy, a dog may show physical signs, while abdominal palpation, blood tests, x-rays and ultrasound can confirm pregnancy. In the final stage of pregnancy, movement may be seen in the dog’s abdomen.
According to WebMD, the gestation period for a puppy is 63 days. WebMD states that by day 40 a pregnant dog may exhibit enlarged, darkened nipples. As early as day 18 or 19 after ovulation, ultrasound may detect pregnancy. Gentle abdominal palpation of the uterus can detect pregnancy between days 28 and 35. A blood test for the hormone relaxin can be done near day 28 until day 30. At day 45, fetal bone structures can be seen on x-ray. The dog’s abdomen becomes enlarged during the final two weeks of pregnancy.