It is awful to smoke when you are pregnant. There are so many risks for the baby. My cousin smoked throughout her pregnancy and her little girl is now 14 months old and she weighs the same as my niece who is six months old, so needless to say she is underweight. Not to mention it has seemed like she has had a cold since the day she was born because she always is congested with a runny nose. It's pitiful, that poor baby didn't ask for that.
Also, you have to think of the with drawls. When you quit you will go through them, so imagine when your baby is born, he/she will have to go through it too. Which could mean that you may have a very agitated baby.
Personally I think that it is very selfish to smoke when you are pregnant and also in the presence of babies and children. So hopefully you do the right thing and quit. Good luck!!!!! It will be hard but definitely worth it. You couldn't have a better reason then know to quit!!!