I think it should be up to her and not something she's pressured into by anyone else. If she feels she can't work then she shouldn't. If she feels she can and/or wants to then she should.

For me, even if money wasn't an issue the only reason I wouldn't work would be if there were genuine health issues that would jeopardize the pregnancy if I did. Otherwise, I like my job and I'd be bored as hell staying home with little/no stimulation. One of my cousins had to do this because she had a high risk pregnancy and she certainly didn't enjoy it.