Do Dogs’ Teats Enlarge When In Heat?

I read in a previous column on how to tell if you dog is pregnant or not. I read that their teats get swollen, but my question is are they swollen when they're in heat as well?

After their first heat a dogs teats will stay a little swollen in comparison to before their first cycle, and in some cases this is more pronounced. I guess the first question to ask is has she had any close encounters with a male? If not then it is probably just her natural state or a phantom pregnancy (which is relatively common at the end of the heat cycle in dogs).