Just a thought. This is an interesting topic as was the length of labor topic and how it is affected by working out. My feelings are whether you go a few more days over the date or whether or not the labor last a little longer is over shadowed by how great one feels the entire nine months of pregnancy. My first four babies were really tough pregnancies because I gained so much weight and didn't move around much. Baby number five was a skip in the park and I know it was due to working out each day - just made me feel so wonderful, sometimes hardly even pregnant. The birth was amazingly easy too for which I'm thankful, although I can't say whether it was due to the exercise or not....but again, the effects of working out make for a much nicer pregnancy in general and I'm sure a healthier baby and mom.
Gotta look at the long term....and I appreciated all your comments too.
Briee
during the beginning of my 5th pregnancy mixed with Firm workouts like the first whole body tape (susan harris) and the not so tough aerobics tapes, and I didn't begin to really weight lift until the sixth month of pregnancy. I built more muscle in those last three months than during the whole prior year. I know I have to be careful advising someone to do too much while pregnant, but it really worked for me, so I'm sure you'll bump right up there with your upper body if you start doing even moderate workouts for upper body. 
