Safe to do 'harder' work?

I have about 3.5 weeks left to go, and I'm wondering what kind of work might
be too much.
There's like 300 feet of snow outside right now. Well, not quite that much,
but I'd guess that there's probably about 6"-8" of snow on the sidewalks out
front. I can't leave the front walks with tons of snow... I feel bad for
the poor mail carrier and although I share the front (and back) walk with
the neighbour, they seem to refuse to lift a shovel for the front OR back.
I left the snow thinking maybe since I did the back walks they would maybe
do the front, seeing as the neighbour has 2 teenaged children. Well, now
there's tons of snow out there, and they need to be done.
Is something like shoveling sidewalks alright to do? There's no way the
sidewalks can be left and ignored for the next month or so. I can't send DS
out there to do them as there's just too much for him.
So, is something like shoveling sidewalks alright to do at this point in
pregnancy?