I'm 36 weeks pregnant and still working and you can go back to work whenever is best for you
I worked up until i went into labor and my water actually broke while i was at work. So I left work went home showered, packed my bags and went to the hospital, I didn't start having contractions until 5 hours later . But depending on how u feel towards the end some ppl take off two weeks before their due date
I'm working all the way till I have my baby girl