I stopped at 30 weeks. My DM had severe pre-eclampsia with my eldest brother and went into labour 7 weeks early so was worried that might happen to me.
Also, I had fallen pregnant immediately after we bought our fixer upper house, so we'd been renovating non-stop. For about 4 months of my pregnancy we were living downstairs whilst upstairs got done. We could afford the building work but not the painting and finishing, so DH and I had to do all that. I was 7 months pregnant, up a ladder, painting my DDs room! Plus we had to get it finished because my MIL came to stay with us the week after my maternity leave started. Not to mention, I had dreadful SPD too.
Having the time off before baby arrived was a godsend. I had loads of time to rest, nest and get everything ready.