Kids whose moms smoked while pregnant were more likely to end up on medications such as antidepressants, stimulants and drugs for addiction in a new study from Finland that hints at maternal smoking's effect on a baby's developing brain.

While the findings don't prove that cigarette smoking during pregnancy causes changes in kids' brains or behavior, they offer one more piece of evidence that should encourage women not to light up while pregnant, the researchers write in the American Journal of Epidemiology.

The new study is "entirely consistent with a large and still-growing research literature on the effects of prenatal and secondhand smoke exposure on the mental health of children", says Dr Michael Weitzman, who studies that topic at New York University Medical Center and was not involved in the new study.