You will notice a number of things during her pregnancy, the first and most obvious being a gain in weight and thickening of the girth.
After 40 to 50 days her teats will start to swell and nearer the 64 day term she might also start to produce milk.
However, the best way of finding out if she is pregnant is to have her scanned by a vet who will then be able to tell you how many pups to expect.
It goes without saying that the bitch’s welfare is paramount during her pregnancy so it’s worth following your vet’s advice on a suitable feeding regime for her and the unborn pups.
Most important of all is to put her on the Panacur worming programme after 40 days to protect her pups’ from parasites and ensure their health both in the womb and at birth.