Aside from the fact that it is prohibitively expensive to do around here (New York), I prefer not to subject the pregnant rabbit to the stress of being handled and examined, if it's not necessary. As long as everything is going well and she looks normal, I prefer to let things progress naturally.
Of course, if the doe is in distress or appears to have a stuck kit or other issue during labor, I wouldn't hesitate to take her in to the vet.