I am a primary teacher and was planning to work up until the end of the term before I was due (term 4 2006) however I ended up having to take leave without pay at 16wks due to heart probs and worked casually until a few weeks before the end of the year. I had one friend who worked up until the week before she was due, she was exhausted and also there was the issue that if she had the baby early who would cover her class??? I think finishing up around 34-36wks is pretty normal