I was 36 weeks when I went on mat leave.

Our work enterprise agreement says that we have to go on mat leave 6 weeks before the due date unless we can get a letter from a Dr saying that we are fit to work. I got a letter signed saying I could work up to 4 weeks before my due date but they were reluctant to sign anything. I found the 4 weeks went really fast and bubs arrived 9 days 'late' anyway.

Hope that helps.