I had a coworker who said the dr told her it is more traumatic (causing withdrawals) if she stopped smoking. We had the same dr and I wanted to ask SO bad, but never did I did ask a different dr and they said that, too, though. So, who knows :/ dumb!
I was a smoker before becoming pregnant and my dr said its ok to have ONE rather than stress about not having one. It wasn't permission to smoke but some people are just so addicted that they do stress out about having to quit. I think she just took that as permission to keep on doing what she wants.