Possible pregnant female?

Question
We have an american pit bull terrier female about 8 months old - not yet spayed. She is an indoor dog and has been to the kennel a couple of times while in heat. We're pretty sure she was not exposed to unneutered males at the kennel. Is there any way to tell if she's pregnant or not? We're hoping not. Her nipples are a bit swollen and she's no longer in heat. Any helpful information would be grateful. Thank you.

Answer
its too early to tell for sure, but sometimes if they get milk around 4 weeks it is a false preganancy.  Otherwise, swelling and rednes in the nipples is the first sign of either a real or unreal pregnancy.  around six weeks you can get an ultrasound and that will show something.  If you don't want a littler ever, then why not have her spayed soon and if she is in the early stages, the eggs won't develop.
nancy