- Enlarged or sagging nipples: If a female dog has recently given birth, her nipples may be enlarged and/or sagging, and may also produce milk when squeezed.
- Belly stretch marks: A female dog's belly may develop stretch marks if she has given birth before, especially if the litter was large or the puppies were born close together.
- Relaxed vulva: The vulva of a female dog that has given birth may be relaxed and appear slightly open.
- Behavioral changes: A female dog that has recently given birth may exhibit behaviors such as nesting, protectiveness, and increased licking of the genital area.
- Milk production: A female dog that has given birth will produce milk to feed her puppies. You may notice milk leaking from her nipples or see her nursing her puppies.
- History from previous owner or rescue organization: If you adopted your dog from a shelter or rescue organization, they may have information about the dog's previous history, including whether or not she has had puppies before.
It's important to note that not all female dogs that have given birth will display all of these signs. Some dogs may only show subtle signs, while others may have more obvious indications. If you're not sure whether or not your dog has given birth before, you can consult with a veterinarian for a more definitive answer.