I dunno-- she could have looked like that any time after seven months. Anyway, previews suggest something major is going to disrupt their lives at the prison, and that doesn't work well (in the dramatic sense) if they only just got there. No emotional investment in the place.
Oh, sure, she could look like that 7 months along, but, there's also the "panicked urgency" to find a place for her to deliver. If she was still 2 months away from delivery, it wouldn't have been presented as so urgent, I don't believe. The first couple episodes gave the impression they were just about expecting her to deliver any minute
One Day I hope to be the Man my Cat thinks I am
Where are we going? And why are we in this Handbasket?