E-cigarettes and nicotine patches are likely to be safe when used in pregnancy to help expectant mothers quit smoking, a new analysis of data has suggested.
The research undertaken by Queen Mary University of London found that the regular use of nicotine replacement products during pregnancy is not associated with adverse pregnancy events or poor pregnancy outcomes.
The findings are published in the journal Addiction.
Smoking when pregnant is associated with a range of adverse pregnancy outcomes, including miscarriage, stillbirth and preterm birth, but the role of nicotine in these effects is currently unclear. Nicotine replacement products, mainly in the form of nicotine patches, are widely used to help pregnant smokers quit; however, there is currently limited data on the effects of these products on pregnancy outcomes, the researchers said.
The researchers analysed data from over 1,100 pregnant smokers who were part of the Pregnancy Trial of E-cigarettes and Patches (PREP 2) study at one of 23 hospitals in England or a stop-smoking service in Scotland. By taking measurements of cotinine levels in saliva at the start of the pregnancy and again towards the end, the researchers were able to determine how nicotine levels affected pregnancy outcomes.
Together with other information about each participant’s use of cigarettes or types of nicotine replacement therapies (NRT) and their respiratory symptoms, as well as the birth weight of the babies, the researchers were able to compare pregnancy outcomes of women who used nicotine in the form of NRT during their pregnancy with pregnant women who used no nicotine.
The analyses show that e-cigarettes were a more popular choice than nicotine patches for women who wanted to quit smoking during pregnancy, with forty-seven per cent choosing e-cigarettes compared to twenty-one per cent using patches.
Regular use of nicotine products was found to have no adverse effects on pregnant women or their babies. Babies born to women who did not smoke during pregnancy did not differ in birth weight, whether the women used nicotine products or not.
In addition, the results showed that women who smoked and used one of the nicotine replacement products during their pregnancy had babies with the same birth weights as women who only smoked.
Lead researcher, Professor Peter Hajek from Queen Mary University, said the trial contributes answers to both practical questions surrounding the use of NRT and other broader questions concerning the current understanding of the risks of smoking when pregnant.
Professor Hajek 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.’
He added: ‘The harms to pregnancy from smoking, in late pregnancy at least, seem to be due to other chemicals in tobacco smoke rather than nicotine.’