How should I plan my course schedule given that my wife is due to give birth during the semester?
Yes, I would say that at the beginning of the course. In my case that was received positively, and when the day came they were very flexible in handling any schedule changes (much more so than students normally are). 

I would also discuss this early on with your collegues. In my case they were very willing to help out (people are much less irreplacable as we like to think we are...)

This is definately something to discuss with HR, as there may be all kinds of policies and programs that you never heard of and could really help you balance your new family life with your work (as a colleage told me: however you will measure it, your life will change significantly (We both teach statistics), and he was right)