- Pregnant women who exclusively vaped had significantly lower levels of 10 toxic volatile organic compounds (VOCs) compared to those who smoked, with reductions between 44% and 97%.
- Levels of most VOCs in exclusive vapers were similar to those found in women who had never used tobacco or nicotine products.
- Dual users (those who smoked and either vaped or used nicotine replacement therapy) had higher toxin levels than exclusive vapers.
- While vaping reduced exposure to many harmful chemicals, researchers cautioned that its safety during pregnancy remains uncertain and further studies on health outcomes are underway.
Pregnant women who switch from smoking to vaping are exposed to significantly lower levels of harmful chemicals, according to a new UK study.
The research, led by scientists at City St George’s, University of London, is the first to comprehensively compare toxicant exposure in pregnant smokers, vapers, and non-users.
The findings, published in the journal Nicotine and Tobacco Research, suggest that exclusive vaping during pregnancy may substantially reduce exposure to some of the most harmful substances found in tobacco smoke.
Urine samples from 140 pregnant women across five UK hospitals were analysed for 14 volatile organic compounds (VOCs). These are chemicals linked to cancer, respiratory illness, and heart disease.
Women who exclusively vaped had dramatically lower levels of 10 VOCs compared to those who smoked, with reductions ranging from 44 per cent to 97 per cent. VOC levels in vapers were also similar to those in women who had never used nicotine or tobacco.
Shifting patterns in nicotine use
Vaping is increasingly used by pregnant women as a tool to quit smoking. While health authorities continue to recommend complete cessation of nicotine use during pregnancy, the new findings suggest vaping is less risky than smoking.
“This is the most rigorous study to date measuring exposure to these toxins among pregnant women who vape compared to those who smoke,” said Professor Michael Ussher, lead author and professor of behavioural medicine at City St George’s. “It shows that vaping results in much lower exposure to certain harmful substances.”
The study included five groups of participants: exclusive smokers, exclusive vapers (who previously smoked), dual users of cigarettes and vapes or nicotine replacement therapy, and women who had never used tobacco or nicotine.
While nicotine levels were similar among all product users, the concentrations of VOCs were notably lower in exclusive vapers and never-users.
Next steps
The researchers cautioned that reduced exposure does not equate to safety. “Just because mothers-to-be are exposed to fewer harmful chemicals by opting to vape instead of smoking doesn’t mean vaping is safe,” said Ussher. “There are still unknowns, and we’re now launching further research into health outcomes for both mother and baby.”
The study also noted that some toxic substances, such as heavy metals and certain tobacco-specific compounds, were difficult to detect or yielded inconclusive results due to low levels in participants’ samples.
As vaping technology evolves, the researchers stressed the importance of ongoing surveillance of emerging chemicals. “Products and patterns of use change quickly,” Ussher said. “We need to keep monitoring for new toxicants that may not have been assessed in this study.”
Funded by Cancer Research UK
The study was conducted in collaboration with researchers at University College London, King’s College London, the University of Nottingham, the U.S. Centers for Disease Control and Prevention, and the UK Health Security Agency. It was funded by Cancer Research UK.
While further research is needed to understand the long-term effects of vaping during pregnancy, these findings provide some of the clearest evidence yet that switching from smoking to exclusive vaping can reduce exposure to harmful substances during pregnancy.
