The length of time that a pit bull stays pregnant is a total of 9 weeks (63 days). The same is true of all dog breeds.
A person is generally able to tell that a pit bull is pregnant between 26 and 35 days after the dog has been bred. This can be detected by feeling around the abdomen. A person may also choose to bring the dog to a veterinarian for a proper diagnosis. Pregnancy is confirmed by performing an X-ray on the female.
Beginning at approximately 45 days into the pregnancy, the mammary glands become swollen and filled with milk prior to the birthing of the puppies.