The use of e-cigarettes or nicotine patches during pregnancy does not seem to adversely affect the foetus. This is according to a major UK study involving over 1100 pregnant women.
"The baby's birth weight was the same as for non-smokers, but significantly higher than for those who continued to smoke during pregnancy," the British researchers state.
Neither e-cigarettes nor nicotine patches affect the foetus when used for smoking cessation during pregnancy. This is according to a randomised control trial study that compared different forms of nicotine use during pregnancy with no nicotine use at all. The study was funded by the NHS.
Missing reality studies
E-cigarettes and other smokeless nicotine products are often used as smoking cessation aids. Especially among pregnant women. Although the use of smokeless nicotine is considered to be less harmful than smoking, there are no real-life studies showing how it affects the foetus in the womb and the expectant mother. Researchers at Queen Mary University London wanted to find out.
1100 pregnant smokers participated
1100 pregnant smokers admitted to hospitals in 23 cities in England and Scotland took part in the study. The researchers gave the women the option of using different tools to stay smoke-free, e-cigarettes or nicotine patches. They then divided the women into three groups. A group that replaced cigarettes completely with e-cigarettes, a group that stayed smoke-free using nicotine patches and a group that continued to smoke to some extent during pregnancy.
"It was found that 47 per cent of women chose e-cigarettes and 21 per cent chose nicotine patches. Some combined the products and others continued to smoke partially while using one of the nicotine products occasionally," the researchers write.
No difference between non-smokers and vejpers
The study began near the 12th week of pregnancy. To check the sample results, the researchers measured the levels of cotinine - a biomarker for measuring higher levels of nicotine in the blood. The samples were taken at the beginning and end of the study and at a follow-up three months after delivery.
Smoking during pregnancy is already linked to lower birth weight and several other birth complications. The results of the study showed that the babies of those who used e-cigarettes and nicotine patches to replace cigarettes had a birth weight similar to that of babies of non-smoking mothers. It also found that those who used alternatives to cigarettes had 45 per cent lower levels of cotinine in their blood compared to the beginning of the study.
Smoking caused complications
Newborns of a smoking mother had blood levels of cotinine as high or higher than at the beginning of the study. This was regardless of whether they vejped or used patches in parallel to reduce cigarette intake. The children of the women in this group also had significantly lower birth weights than children in the other groups. The average weight was 3.1kg compared to 3.3kg.
The researchers also compared the incidence of other complications related to smoking and newborns. Those who vejpook or used nicotine medicines did not differ, as a group, from non-smokers. However, there were some differences compared to smokers, although complications were low in that group as well.
"E-cigarettes help pregnant smokers to quit smoking, without posing any demonstrable risks to pregnancy. This is true even compared to quitting smoking without nicotine use." says Peter Hajek, an addiction researcher and one of the researchers who led the study. "Thus, using nicotine-containing aids to stop smoking during pregnancy appears to be a safe method. The harm from smoking during pregnancy, at least in the later stages, appears to be primarily due to other chemicals in tobacco smoke, rather than nicotine." concludes Peter Hajek.
Same level of risk as nicotine medicines
Unlike the Swedish authorities, British health authorities currently recommend that pregnant smokers use smokeless nicotine. At least to the extent that they are unable to quit smoking by other means during pregnancy. However, many midwives and doctors have been reluctant to recommend e-cigarettes to pregnant women. This is despite the fact that, according to the UK Public Health Agency, the risks are at the same level as other smoke-free, medicalised nicotine products.
"Women who continue to smoke during pregnancy do so because they find it very difficult to quit. This is why it is important that doctors, pregnant women and their families are informed that it is indeed safe to use nicotine replacement products or e-cigarettes during pregnancy," said Mr Perez. Linda Bauld, co-author of the study and Professor of Public Health at the University of Edinburgh.
The study was funded by government National Health Service and was recently published in the journal Addiction.
Sources for this article:
Addiction: 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
Queen Mary University of London: Nicotine replacement products offer safe quit option for pregnant smokers
Facts about the study:
Participants who chose e-cigarettes in the study received a refillable starter kit (a simple mouth-to-lung system from the One by UK E-cig Store, with a power output of 14 watts) and two 10 ml bottles of flavoured e-liquid (18 mg/ml nicotine). Additional supplies of e-liquid were sent on request for up to 8 weeks. However, participants were allowed to purchase and pay for any spare parts after 8 weeks.
Participants who chose the nicotine patch received an initial 2-week supply of Nicorette Invisi 15 mg/16-hour nicotine patch. Additional supplies were available upon request for up to 8 weeks. Participants were encouraged to access additional supplies of patches and/or other NRT products through their GP or local stop smoking centre. In the UK, pregnant smokers receive NRT free of charge.
