NO it is NOT in bad taste!!! It is such a thoughtful and kind thing to do!!! The hardest part of losing a child might just be that no one wants to talk about it, that you do not feel like your child touches anyone anymore, that you are expected to keep it all to yourself.
I compeletly encourage you to send her a card and give her a call or whatever you want to do. It will fill her heart and let her know that she has a true friend who cares for her, even when it is difficult and uncomfortable.
She needs to be able to grieve and there are most people don't want to give her the space to do that. The baby was alive, it was hers, and it is still in her heart. There is no way that she isn't going to be thinking of it. There is no way that she's free from the fact of losing her baby. You are a wonderful friend to acknowledge something so difficult and to be there for her. Everyone should have a friend like you!