With my first pregnancy my due date was supposed to be 25 September, I advised my employer that I would leave a month before that and did so. Unfortunately for me, my daughter came on the 7th, leaving me only with 10 days leave (but she also ensured that she was a nice 6 pounder rather than the promised 8).

So when you plan your leave, it may pay to calculate in early arrivals too.

I have also found out that I must be back in continuous employment for 12 months before I am eligible for maternity leave again. I found that in the workplace agreement at my place of employment. It's useful to know something like that when you have returned from mat leave and are planning another one.