As far as I know the only thing that can harm a fetus when mum has the flu is a high fever. So if you keep any temps under control you should be OK. Fevers in pregnant women have been recently linked to the adult children having mental illness. It was probably only one study that had those findings, but it certainly is interesting.

Our household just had the virus doing the rounds of Melbourne at the moment and it wasn't nice. I'd sleep in another room just to be safe.