A new analysis of trial data from over 1100 pregnant smokers, led by WIPH researchers, finds that the regular use of nicotine replacement products during pregnancy is not associated with adverse pregnancy events or poor pregnancy outcomes.
The PREP 2 study used data collected from pregnant smokers attending 23 hospitals in England and 1 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.
Lead researcher, Professor Peter Hajek said: ‘The trial contributes answers to two important questions, one practical and one concerning our understanding of risks of smoking. E-cigarettes helped pregnant smokers quit without posing any detectable risks to pregnancy compared with stopping smoking without further nicotine use. Using nicotine containing aids to stop smoking in pregnancy thus appears safe. The harms to pregnancy from smoking, in late pregnancy at least, seem to be due to other chemicals in tobacco smoke rather than nicotine.’
The study, conducted by researchers at Queen Mary University of London, University of New South Wales (Australia), University of Nottingham, St George’s University of London, University of Stirling, University of Edinburgh, and King’s College London, and St George’s University Hospitals NHS Foundation Trust, analysed data collected in the Pregnancy Trial of E-cigarettes and Patches (PREP) randomised controlled trial, funded by the National Institute for Health and Care Research (NIHR).
Francesca Pesola, Katie Myers Smith, Anna Phillips-Waller, Dunja Przulj, Christopher Griffiths, Robert Walton, Hayden McRobbie, Tim Coleman, Sarah Lewis, Rachel Whitemore, Miranda Clark, Michael Ussher, Lesley Sinclair, Emily Seager, Sue Cooper, Linda Bauld, Felix Naughton, Peter Sasieni, Isaac Manyonda, Peter Hajek. 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) randomised controlled trial. Addiction. 17 January 2024.
https://onlinelibrary.wiley.com/doi/10.1111/add.16422