I have no advice on ergonomics but I worked right up until delivery with all 3 pregnancies. I didn’t have any paid time off with the first two and only two weeks paid vacation with the 3rd so I couldn’t afford to take off until they were actually here. How long you are able to work all depends on the person and possibly the pregnancy. I did do frequent visits to the chiropractor. I worked full time and I never had any pain or discomfort due to pregnancy.
I also worked up to the days of delivery for all three of my pregnancy’s and I felt that my posture was better because you had to sit up straighter to avoid belly bumping the patient’s head