Any pregnant mamas that plan to continue running during pregnancy?

I just got back into running a couple months ago and would love to keep it up. Anyone have experiences with this, or is on the same boat?  I stopped running during my first pregnancy when the first trimester fatigue got to me. Would love to hear past experiences- at what point did you have to modify or stop running?  I am not a long distance runner -- a 3-4 mile run is perfect for me.