For me I'd be looking at how much time needed to be set aside for study / assignments etc - and working it out from there.
If this is bubs number one for you then it may be a little easier to get time for study, even more time if your partner is a 'hands on' kinda dad .

I've just spent the last 6 weeks studying at every opportunity for a big exam I had yesterday and I think I almost turned into a witch from the pressure of trying to study, but having either DD or DS needing me! I'm so glad its over now!

Good luck!!