My son's birthday is October, and he was born in St. Louis, so it was hot when I was starting to get really huge. My doctor let me keep riding bike paths (Katy Trail) and in town (this was 1998, so my Fisher had no suspension). She told me to keep hydrated and fed, and no riding on RR tracks.

Of course, the bigger I got the more I rode across the RR tracks in Sept...but it didn't help (or hurt) and he still was a c-section.

As long as you're sensible, I would expect your doctor to OK your riding.