It is something to give lots of thought to. With my first I worked until 36weeks. I lifted and did very physical work. I didn't have any issues until the last couple of weeks when my blood pressure went up and my Dr. said no more working. It really depends on you and your doctor. As far as climbing ladders, I wouldn't. But I had a miscarriage before this pregnancy so I am much more cautious this time around.
Talk to your doctor and your employer, then you can make a more personal decision.
Wow they put the time you work towards your maternity leave? I don't think my job does that. My BFF had a baby 4 years ago at our job so i will ask her. I have about 44 hours of sick/personal/vacation time left. I have until mid-may to use up the remaining vacation time and the sick/personal is ongoing, another 4 hours posts each week. In mid may another 80 hours vacation posts & I have both short & long-term disability.