Hi k8
Originally I was due to start my maternity leave with 6 weeks to go, however my partner did his back in and I ended up over doing things a bit at home and the doctor signed me off untill my maternity leave is due to start, so I now have 8 weeks to go.
Everyone is different but I thought I'd be fine right up untill my due date but actually even if partner hadn't of done his back in I still would've found it hard at work because I'm so big now. Most people usually go for 4 weeks or less, but if your a weed like me you'd want to take as long as possible before your due date, bearing in mind it will affect how long you get the other side.
Good luck x