In many cases smoking during pregnancy can even result in premature birth, miscarriage or even fetal brain damage.
Smoking whilst pregnant may also bring about high blood pressure in the baby, learning difficulties, developmental difficulties, mental retardation, and respiratory disorders such as asthma.
The problems of being a smoker during pregnancy do not cease at childbirth. Your milk supply will be reduced and therefore the baby will be without its natural nourishment. What milk it can get from breast feeding will contain nicotine and will be poisoning the baby more and causing cramps, colic, diarrhea and nausea. The baby will have the same need for nicotine you have only it will not be able to satisfy its addiction as you are. The baby will have to pass through what you were unable to do whilst pregnant.
If you are not strong enough to stop smoking whilst you are pregnant, (that includes any occasional cigarettes) then after having read this you are knowingly going to make your defenseless child pass through the withdrawal symptoms that you were unable to pass through. That in my opinion makes you an evil person who doesn't deserve to have a child.