I'm now 36 weeks pregnant with my first baby. There are 3 of us expecting at the practice I work at, me being due 3rd Nov, my friend due 4th Nov and another nurse due in January! I am the only one currently now not working....At 31 weeks I was diagnosed with SPD and was really struggling a lot, even just working 2 days in surgery and 3 days on reception. I was signed off until my maternity started! There is no way I'd be able to work with the amount of pain I'm in on a daily basis - all the more reason for me being impatient for the arrival hehe! I wanted to work right up until the due date originally but things change!
My friend is still going strong though, has good and bad days. When I was still working we shared a surgery and that helped. We had each other to ask for help as we both understood how each of us were feeling but you should be able to ask anyone from your team to perhaps run upstairs to develop an x-ray for you, or bring some stock down that you need when they next go that way.
I always made the dentist aware if I was having a bad or slow day so he was aware. As the dentists sit all day long and we run around like headless chickens, they don't seem to understand how energetic our job is and carrying around the extra baby weight can make running around much more difficult.
Do you sit or stand while chair side? I had to stand as there was no room for my seat but the natural of my dentist meant I was sat down a lot typing notes etc so standing chair side wasn't too bad, so long as it wasn't a hugely long treatment.
Make sure you get plenty of time to have a drink too and where you can grab a snack to keep you going.
Don't be afraid to ask your dentist to pick something up off the floor should he/she or you drop something. Bending down is HARD haha! I was always too frightened to ask as the dentist I worked with was the sort of dentist to make me aware and expect me to pick it up (even with a big bump!!) but if I'd have still been at work there is no way I'd be able to bend down all day long picking things up so I would have had to find the courage to ask
I hope this advise helps and all goes well with working during your pregnancy and the pregnancy itself