When your pregnant dog's nipples start dripping milk, that's one sign she'll soon be going into labor. However, it's not the most accurate -- some dogs, especially first-time mothers, might drip milk several days before delivery. There are more reliable methods to determine whether labor is imminent.
Canine gestation lasts approximately 63 days, although a few days earlier or later is normal. If you know when your dog was bred, you have a good idea of her due date. As her due date approaches, watch for signs that she's going into labor. The initial stage of labor can last 12 hours or more, so you'll have time to make any necessary preparations.
The most reliable way to determine if labor is imminent is by taking your dog's temperature twice daily -- mornings and evenings -- as her due date approaches. Normally, her temperature should range between 101 and 102 degrees Fahrenheit. When her temperature drops below 100 degrees, labor should proceed within 24 hours.
When early labor starts, the dog becomes very restless. She might pace, whine or become quite clingy. She doesn't want to eat, and might demonstrate nesting behavior. Some dogs would rather not have people around and find a secluded spot to stay in.