The authors identified limitations to their analysis.
1) Only a single outcome was considered. If other adverse effects of smoking on babies were included, the cost effectiveness of smoking cessation programmes increased.
2) Cost and complication rates were averages and not adjusted for potential effect modifiers.
3) The study focused only on the short term positive effect of smoking cessation on pregnancy outcomes and underestimated true cost effectiveness.
4) The model was limited to smoking cessation achieved only in the first trimester.
Moreover a)The research method of the effectiveness data should have been reported in more detail and the method of synthesis for these data should have been more rigorous.
b)Insufficient detail was given for calculations of health service costs for the care of low and normal birthweight babies.
c)External validity was dependent on female smoking rates and cost structure in other countries.
d)The economic study type was not a cost-benefit analysis, as the authors stated, but a cost-effectiveness analysis, since benefits were not expressed in monetary terms.