uh oh, unwanted pregnancy (potentially unhealthy)

Question
Our 9 month old yellow lab finished her first heat 4 weeks ago, we were very careful of her comings and goings during that period so we are pretty sure (90% sure lets say) that she did not get into contact with males during the dangerous period. She did run away once for about twenty minutes but a neighbor 1 street corner away picked her up 5 minutes later and brought her back. So again, we are pretty sure but not 100% certain that she didn't have contact with a male. Now yesterday, my wife noticed that she had swollen nipples (our dog), and it got us thinking of how her overall mood had been a bit different for the past week.

Now the actual questions: short of going to the vet, is there a surefire way to verify if she is pregnant?
Also, if she is pregnant, I know that she is definitely too young to have a litter, what are the risks to her health and that of the potential pups?
Also, should we go to the vet and have her aborted?
Is there a legal limit or a or a time by which it becomes dangerous for her to have an abortion?

Answer
The nipples will change on a bitch after her first heat, so that's not necessarily a sign that she is pregnant.

You can go to the vet at about 28 days after what you think was the breeding day, and they can do a blood test to see if the dog is pregnant.  

For dogs, doing an "abortion" would be actually spaying the girl and removing the fetuses.  While I think spaying would be an excellent idea, it IS a tough surgery because there is alot of blood flow to the uterus at this time, IF she IS pregnant.  

While not IDEAL to have a litter at this age, she faces no more risks than if she had pups later in life, however, MENTALLY she may not be a good mom, so if you do have to have a litter, you may need to be prepared to be a bit more hands on with the pups than if she had been more mature.

I would call the vet today, let them know what you think happened and let them suggest a course of action for you.  Good luck.