The habit of cigarette smoking is more intensive. The dependency is more than a habit - it's a drug addiction. If a smoker survives past the age of 55, their life is extended up to 15 years longer than nonsmokers. There are claims to lower birth weights. Doctors used to prefer lower birth weights because of easier and less painful deliveries.
Common sense comes into play here.
Don't smoke during a pregnancy - not because of a possible lower birth weight, but because deep breathing during delivery won't generate coughing. The rudeness of both non-smokers and smokers is shocking. Even your hair stinks. This is sometimes said through a breath reeking of an alcoholic beverage. Or even by a person whose perfume or after-shave permeates the air.