I would speak your mind, and then deal with the icyness.
It's HER baby, does that mean she is going to let it do all sorts of unthinkable things?!? It's HER baby so shouldn't she want what is the absolute best for the child that is within her power to acheive!!
It doesn't sound like it would be impossible for her to give up smoking. I wish she was in Australia, our hospital staff and doctors would tell her exactely what is what about being so stupid as to smoke while pregnant.
My husband smokes and they would give him a talking to about it!
Hormones?? Hormones are meant to make us care more about our child. She sounds like a selfish person who obviously knows that what she is doing is wrong because she's so sensitive about it.
What is there to be understanding about? Negligence!?!?
I'm sorry, this just really gets my goat.
You don't even have to tell her exactely what you think, just say I'm sorry I don't agree with you and turn away. She'll know.
Best of luck dealing with this one.