Methods to determine pregnancy in pet dogs:

1. Observe the physical changes. The nipples of pregnant dogs will become pinker, more swollen and more prominent than usual. The dog's body shape usually doesn't change until the 4th to 5th week. The waist will become thicker and the belly will gradually protrude.

2. Gently stroke the dog’s belly with your hands. The best diagnostic time for this touch method is the 28th to 35th day after pregnancy. Before this, the fetus is still too small to be easily noticed. After that, it is easy to be confused with food in the intestines and the like.

3. From the sixth week of pregnancy, veterinarians can use a stethoscope to monitor the heartbeat of the baby dog. But it's far more difficult than listening to the heartbeat of a baby in your belly. Because the dog has thick fur and its belly is round, it is not easy for the stethoscope to completely stick to it.

4. Through blood test. The purpose of the blood test is to see if your dog’s blood contains a pregnancy hormone called relaxin.

5. Through ultrasound. A skilled sonographer can detect a baby in a dog's belly starting on the 16th day of pregnancy.