Usher Institute

E-cigarettes help pregnant smokers quit without risks to pregnancy

New analysis of data shows pregnant smokers using nicotine replacement products face no adverse outcomes.

A new analysis of trial data on pregnant smokers finds that the regular use of nicotine replacement products during pregnancy is not associated with adverse pregnancy events or poor pregnancy outcomes. The research was led from Queen Mary University of London and included contributions from Linda Bauld and Lesley Sinclair, both from the Usher Institute at The University of Edinburgh and SPECTRUM Consortium.

The PREP 2 study, funded by the National Institute for Health and Care Research (NIHR), used data collected from over 1100 pregnant smokers attending 23 hospitals in England and one stop-smoking service in Scotland to compare pregnancy outcomes in women who did or did not use nicotine in the form of e-cigarettes (EC) or nicotine patches regularly during their pregnancy. Researchers took measurements of salivary cotinine levels at baseline and towards the end of pregnancy, and gathered information about each participant’s use of cigarettes or types of NRT, respiratory symptoms, and the birth weight and other data of their babies at birth.

The study found that e-cigarettes were more commonly used in the group studied than nicotine patches (47% compared with 21%), and also confirmed previous unexpected findings that EC use may reduce respiratory infections in vapers, possibly because the main ingredients of EC, aerosol, propylene glycol, and glycerine, have antibacterial effects.

Women who smoked and also used one of the nicotine replacement products during their pregnancy had babies with the same birth weights as women who only smoked, while babies born to women who did not smoke during pregnancy did not differ in birth weight, whether the women did or did not use nicotine products. Regular use of nicotine products was not associated with any adverse effects in mothers or their babies.

Clinicians, pregnant women and their families have questions about the safety of using nicotine replacement therapy (NRT) or e-cigarettes during pregnancy.  Women who continue to smoke during pregnancy often find it difficult to stop but products like NRT or e-cigarettes can help them to do so. These results suggest that NRT or vaping can be used as part of a quit attempt without adverse effects. Our findings should be reassuring, and provide further important evidence to guide decision-making on smoking cessation during pregnancy.

Professor Linda BauldBruce and John Usher Chair of Public Health, The University of Edinburgh’s Usher Institute and Director of SPECTRUM Consortium

Further information

Read the full paper

Read Queen Mary University of London’s press release

SPECTRUM Consortium

National Institute for Health and Care Research

Cite as

Pesola F, Smith KM, Phillips-Waller A, Przulj D, Griffiths C, Walton R, et al. Safety of e-cigarettes and nicotine patches as stop-smoking aids in pregnancy: Secondary analysis of the Pregnancy Trial of E-cigarettes and Patches (PREP) randomized controlled trial. Addiction. 2024.