Using e-cigarettes could be a better option than nicotine patches to help pregnant women stop smoking and reduce the risk of low birth weight, according to research by Queen Mary University of London.
Current guidelines recommend that pregnant smokers who find quitting difficult should be provided with nicotine replacement therapy. Stop-smoking services usually recommended nicotine patches to help pregnant women stop smoking.
The study, published in NIHR Journals Library, set out to compare the effectiveness and safety of nicotine patches and e-cigarettes in pregnancy.
The pragmatic multi-centre randomised controlled trial involved 1140 pregnant women who were 12 to 24 weeks' gestation and who smoked daily. Participants were recruited from 23 hospitals in England and one stop smoking service in Scotland.
Half of the women were sent a refillable e-cigarette device in the post with two 10 ml bottles of tobacco-flavoured e-liquid containing 18 mg of nicotine. The other half were sent a 2-week supply of 15 mg/16-hour nicotine patches. Supplies for both groups continued for up to 8 weeks.
All the participants received support phone calls prior to their target quit date, on the quit date, and weekly for the next 4 weeks.
E-cigarettes "Seem More Effective Than Patches"
Sustained abstinence rates were found to be low — 6.8% for those given e-cigarettes, versus 4.4% for those provided with nicotine patches — due to only just over half (55%) of self-reported abstainers returning useable saliva samples. This made validation of smoking status via postal saliva sampling "problematic", the researchers noted.
They emphasised that in the unadjusted primary analysis, quit rates in the two study arms were not significantly different, and therefore there was "insufficient evidence" to confidently demonstrate that vaping was more effective in helping pregnant women quit than nicotine patches, and that any benefit seen could have been "due to chance".
At the end of their pregnancy, some of the women reported that they had stopped smoking using a product they were not assigned – mostly in the group who were given nicotine patches, who also vaped. However, after controlling for this, for successful quitters who only used the treatment they had been allocated, almost twice as many had quit with e-cigarettes than had quit with nicotine patches – 6.8% versus 3.6% [Risk Ratio 1.93, 95% 1.14 to 3.26].
Peter Hajek, director of the health and lifestyle research unit at Queen Mary's Wolfson Institute of Population Health, said: "E-cigarettes seem more effective than nicotine patches in helping pregnant women to quit smoking and because of this, they seem to also lead to better pregnancy outcomes."
The authors reported they were unable to assess the value of the support offered to the women, as many participants did not make sufficient use of it. Around 30% of participants did not set a target date for quitting, they noted.
E-cigarette Use Associated with Fewer Low Birth Weight Babies
The researchers also looked at safety outcomes — including low birthweight, baby intensive care admissions, miscarriage, stillbirth, and premature birth — and reassured that both e-cigarettes and nicotine patches were "equally safe".
The only meaningful difference they found was that fewer women in the e-cigarette group had children with low birthweight – 9.6% versus 14.8%. They suggested that the most likely explanation was because e-cigarettes were more effective in reducing the use of conventional cigarettes compared with nicotine patches.
E-cigarettes could be seen as a form of nicotine replacement therapy, the authors said, but had an "advantage" over nicotine gum and patches in that they allowed smokers to select the "strength and flavours they like", easing transition to stopping smoking.
"The evidence-based advice to smokers already includes, among other options, a recommendation to switch from smoking to e-cigarettes," Professor Hajek pointed out. "Such a recommendation can now be extended to smokers who are pregnant as well," he said.
Asked to comment for Medscape News UK, John Waldron from Action on Smoking and Health (ASH), stressed that helping women to quit smoking was an "urgent priority".
He said the study findings should help reassure pregnant women and professionals that vaping can play a role in "helping women to stop smoking during pregnancy, saving babies' lives".
Funding for the study was provided by the National Institute for Health and Care Research (NIHR).