Running mom to be question

Ktrunnergirl

I ran my first mmarathon a few weeks before we found out that we were expecting.  Since then my running has taken a hit, not that I didn't expect it to. The first trimester I was so tried I ran only 2 days a week.  Now, well into my second trimester I have my energy back, but my lungs are feeling the changes in my body big time. 

Long story short, for you other running moms how long did you continue to run while you were pregnant?  Should I start to get use to doing something else or keep going until its too uncomfortable?