I stopped at 32 weeks last pregnancy. I work in emergency medicine, on my feet, and the stress and the emergencies and the shifts were killing me.
I also knew it would be the only time for a very very long time I'd have to myself!
Weeks 32-37 were wonderful, I read lots of books, relaxed, saw all my friends, got loads of energy back and did lots of yoga and swimming. It was lovely and I was in such a better frame of mind when baby arrived.Was a bit grumpy from week 37 onwards but I guess that's standard! Baby arrived a few days after my due date.
I was fortunate enough to be able to afford a year off. It was still hard going back when baby was 10 months old.
This pregnancy I worked till 36 weeks and I was really really feeling it the last week or two. I am part time now so I did a lot of collapsing on my days off, put toddler in nursery for extra days (felt very guilty about this). But finances are tighter this time round so I pushed through.
In some ways I am very glad I stopped at 32 weeks that first pregnancy because I had such a great summer. In other ways I resent my work for not being more accommodating and trying to find me more suitable work - I would have worked later if they had. I tried but they were not helpful. That should be your first port of call though, if you would rather continue working - arrange a risk assessment with your line manager - this should cover things like long hours and being on your feet. THey have a duty to give you suitable work and if they can't technically you should be suspended on full pay. I say this as it is true, but I didn't really manage to make it work for me, so I understand in the real world it is different… I did manage to get signed off night shifts so maybe you could get signed off weekends?
If your work are unhelpful another option is going to your GP, they could write you a sick note for amended duties specifying no shifts longer than x hours, no weekend work. again this is then reliant on you actually leaving on time etc, which I had agreements for but was unable to when a patient is extremely sick, so it did me no good at all! But a couple of options to consider.
If you want 'permission' to stop working at 32 weeks cause it just sounds bloody great - well you have mine! Pregnancy is fucking hard work!