Hi Jenn -- first off congrats. When my SO (also named Jen) was pregnant, she cycled into her seventh month but with a couple of precautionary measures:
- she rode on our local multi-use trail, not the surface roads
- i was running alongside (training for a 10k)
- she was on an Elektra cruiser with an upright riding position which was way more comfortable than a road or mountain bike
Once she started getting into the third trimester, her equilibrium began to go wobbly and she stopped riding as soon as it stopped feeling safe. But up until then she was happy for the exercise and didn't run into any problems.

As far as commuting to work goes, I guess it would really depend on the distance and the route. But for sure the absolute "no cycling" restrictions are overstating the case.