This study looked at 56 pregnant women, and found that those who smoked 6 or more cigarettes a day had babies at birth that were a) lower in birth weight, b) more jittery, and c) show more signs of stress. Comment: what's new about this research is the low threshold of 6 to 7 cigarettes a day. This gives pregnant women another reason to quit smoking completely, and society another good reason to try to prevent tobacco addiction. [ ScienceDaily News Release: Nicotine Changes Newborn Behavior Similar To Heroin And Crack (a report on a study in the journal Pediatrics ]