Anticipating the birth of a litter of puppies can be exciting and nerve-wracking. You are anxious for your female, worried about potential problems with the whelping and looking forward to seeing the puppies—the result of all your planning. While not every bitch will show every characteristic of impending labor, and some won't show any, there are signs that are common in most females and will give you an indication of when to expect the whelping process to begin.
Your female may lose her appetite and refuse to eat a day or two before she gives birth to her puppies. Not all bitches do this; some will eat with relish until they whelp. She will be on smaller meals several times a day by this point, so it is easier to pinpoint when she stops eating.
Starting up to a week prior to whelping, your female may start scratching at the ground or digging. In the wild, canines often dig holes for whelping; nesting is an instinctive behavior. If you haven't already, this is the time to introduce her to the whelping box. Let her shred the newspapers or arrange the blankets however she wants for now. You may need to keep her on a leash when she goes outside during this time—some bitches try to dig whelping holes underneath shrubbery, decks or porches.
Panting and Shivering
As whelping approaches, a bitch's hormones go through dramatic changes. Panting and shivering are common responses to these hormonal fluctuations. Your female may exhibit light panting and shivering on and off a few days before giving birth; this will become more consistent and intense as whelping draws near.
A bitch's progesterone is elevated throughout pregnancy. Twelve to 48 hours before whelping, progesterone levels will drop sharply, to below 2 ng/ml. If there is a concern that the whelping is not progressing as it should, testing your female's progesterone level will tell you whether or not she is ready to whelp.
The sudden drop in progesterone causes a similar, though not as dramatic, drop in temperature. The week before your female is due to whelp, take her temperature at least twice daily and record the results. During the last few days, checking the temperature three or even four times a day will help to pinpoint the temperature drop. A normal temperature for dogs is 101 to 102.5 degrees Fahrenheit; a bitch's temperature may be around 99 degrees in the week before pregnancy. When the temperature drops a full degree and stays lowered, whelping should occur within the next 12 to 24 hours.