i'm gonna guess that i might be the only one here with personal experience with this.
ok, she should not start any new, strenous or taxing activity now, while pregnant. if she had been lifting weights, it is ok to continue lightly with some things, but since most women put the health of their baby above their love of lifting, most don't continue.
She should, however, start a walking program. be consistant and don't overdo it. just a 30-60 minute walk every day would be fine. she will need a strong back and arms/shoulders when the baby is born, so unweighted ab and lower back work is helpful- just have her do some situps and use some machines for lats, shoulders and biceps.
NO deadlifting or squats. There is just no reason to.
before she does anything though, she really does need to ask her doc for a whole bunch of reasons. there are some very common conditions where she should not be lifting much of anything, including machine work.
good luck.