Re: How close to due date did you keep working?
With DS1, I taught (college classes- not physically demanding) the day before he was born, so 42w4d. I hadn't told anyone at work my real EDD, though, and they understood I would probably be working until the baby arrived.
With DS2, it worked out that I could take the semester off. And DS3 was born over the summer when I usually don't teach anyway.