Hello, I would be happy to help you with your question.
If you have used condoms without fail during the entire 11 months AND you are breast-feeding twins, then the chance of pregnancy
is EXTREMELY low. I would say that it is virtually impossible. Also, if the urine pregnancy test sits long enough, it will turn faintly positive - that is why it should be read immediately and not after it has been sitting for a while (this is explained in the test instructions). That all being said, it would probably be a good idea to get a blood pregnancy test to be sure.
I hope that this helps. If you have more questions, please click on "ASK ME A QUESTION" link above to directly ask me a question!