On 2016 Nov 02, Peter Hajek commented:

The finding that stop-smoking medications had beneficial rather than adverse effects on pregnancy outcomes is an important contribution. However, despite the claim in the Conclusion, the study does not really provide any information on their efficacy for smoking cessation. Medication users were trying to quit and an unknown but possibly large proportion of them were already non-smokers at intake (data on this crucial variable are not provided). The control group were all smokers. They were also not engaged in stop-smoking treatments and so likely to have a lower interest in quitting than those taking stop-smoking medications.

On 2016 Nov 02, Peter Hajek commented:

The finding that stop-smoking medications had beneficial rather than adverse effects on pregnancy outcomes is an important contribution. However, despite the claim in the Conclusion, the study does not really provide any information on their efficacy for smoking cessation. Medication users were trying to quit and an unknown but possibly large proportion of them were already non-smokers at intake (data on this crucial variable are not provided). The control group were all smokers. They were also not engaged in stop-smoking treatments and so likely to have a lower interest in quitting than those taking stop-smoking medications.