A new analysis of trial data on pregnant smokers, led by researchers at Queen Mary University of London, has found 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 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 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, published in Addiction Journal, found that e-cigarettes were more commonly used in the group studied than nicotine patches (47% compared with 21%). 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.
“The trial contributes answers to two important questions, one practical and one concerning our understanding of risks of smoking,” Professor Peter Hajek from the Wolfson Institute of Population Health, Queen Mary University of London and lead researcher, said.
“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).