Mothers-to-be who use certain flavours of vapes may be twice as likely to suffer a miscarriage, a disputed study has claimed.
Health data taken from 600 pregnant women suggested those who used menthol and mint flavoured vaping liquid were at most risk.
It prompted the researchers to state that vaping women should be encouraged to quit ‘prior to and during early pregnancy’.
But leading experts have today criticised the research, calling it ‘irresponsible’ and ‘nonsense’.
Vapes have long been hailed as a healthier alternative to traditional tobacco — and even the NHS has said expectant mums should use them over cigarettes.
A controversial US study found women who vape while pregnant were more likely to suffer a miscarriage depending what flavour they chose
But health authorities have cautioned that the long term effects of using the devices are still unknown.
It comes just days after the UK’s chief medical officer, Sir Chris Whitty, demanded a crackdown on marketing tactics that are leading to a kid vaping epidemic.
Academics from a trio of US universities used data gathered by a long-running study on smoking and vaping.
Around 600 women who had recently been pregnant were analysed — including a fraction who vaped while expecting.
No significant differences were spotted between vapers and non-vapers overall in terms of foetal deaths, a category that included miscarriages and abortions in the study.
But there was a heightened risk when they looked solely at different vaping flavours, their analysis suggested.
Women who used mint- or menthol-flavoured vapes during or just before pregnancy were 227 per cent more likely to suffer a foetal death compared to other flavours.
The authors said the results for candy-flavoured vapes were also associated with a higher risk of both foetal death (27 per cent), but, writing in the medical journal Preventive Medicine, they added this result was not ‘statistically significant’.
The exact mechanism for why menthol- and mint-flavoured vapes could cause this effect wasn’t determined in the study.
The authors cited previous research that suggested chemicals used to flavour vapes could cause inflammation in the body and damage cells as one potential mechanism behind the rise in risk.
Previous studies have found some of the chemicals used in mint-flavoured vapes are carcinogenic.
While adding that more research needed to be done, the authors said their results showed healthcare providers should encourage women to quit vapes both while trying to conceive and during pregnancy.
‘Healthcare providers should encourage e-cigarette users to quit prior to and during pregnancy,’ they wrote.
But experts today warned of a catalogue of flaws in the study, including its small sample size and the fact it included abortions in the foetal death data.
Professor Michael Ussher, an expert in behavioural medicine at St George’s University of London who is studying vaping and pregnancy, said: ‘This study is not designed in a way that can assess whether vaping in pregnancy is associated with adverse birth outcomes.’
One in 10 secondary school pupils are now vape-users, despite the uncertainty surrounding their long-term impact on health
NHS Digital, which quizzed nearly 10,000 students aged 11 to 15 on their smoking, drug and drinking habits last year, found that nine per cent currently vape — the highest rate logged since the survey began in 2014
Prevalence of vapes — which can contain as much nicotine as 50 cigarettes — has doubled among kids in less than a decade (Pictured: Elf bars)
He said as the level of traditional smoking was not included among those who vaped the reason for the observed rise in foetal deaths couldn’t be determined.
‘Dual smoking and vaping is common and it is possible that the findings are due to high levels of smoking in the “vaping group”.’
Professor Lion Shahab, an expert on health psychology at University College London and a past president for the Society for Research on Nicotine and Tobacco- Europe, also criticised the study.
He added that it failed to account for other factors that could influence the outcome of pregnancy, such as exposure to second-hand smoke in the home.
Professor Shahab also homed in on the results for alcohol flavoured vapes reducing risk of foetal death as another example that the data might not be reliable.
What do the recent studies on e-cigarettes say?
People who vape experience ‘worrisome changes’ in their blood pressure
Vaping causes your blood pressure and heart rate to spike immediately afterwards, a study claimed.
University of Wisconsin experts found vaping and smoking cause people’s heart rates to spike 15 minutes after use and put the body in ‘fight or flight’ mode.
The study, presented at the American Heart Association Scientific Sessions 2022, looked at data for 395 participants — 164 vapers, 117 smokers and 114 who had no history of nicotine, e-cigarette or tobacco use.
Co-lead author Matthew Tattersall, an assistant professor of medicine at the university, said: ‘Immediately after vaping or smoking, there were worrisome changes in blood pressure, heart rate, heart rate variability and blood vessel tone (constriction).’
But the study has not been peer-reviewed and was only observational, so researchers could not prove vapes were actually causing the heart issues.
E-cigarette users are less fit than people who do not vape
Vapers perform worse when exercising than non-smokers and are more akin to smokers, a study claims.
Researchers looked at data from the same participants as the previous study.
After 90 minutes on the machine, they were given four heart screenings to determine overall health of the organ.
People who vaped scored 11 per cent lower than those who did not use nicotine.
Smokers had test scores 16 per cent lower than the control group.
Dr Aruni Bhatnagar, a professor of Medicine at the University of Louisville said: ‘These studies add to the growing body of science that shows similar cardiovascular injury among people who use e-cigarettes and those who smoke combustible cigarettes.’
Vaping is ‘just as bad as cigarettes for your heart’
Vapers are at the same risk of heart disease as cigarette users, according to US federally-funded research.
In two studies, one on mice and one on people, e-cigarettes were found to cause similar damage to blood vessels as smoking tobacco.
The findings from experts at the University of California, San Francisco were published in the American Heart Association’s journal Arteriosclerosis, Thrombosis and Vascular Biology (ATVB).
Despite the difference in ingredients that make up e-cigarette aerosol and cigarette smoke, the researchers found that blood vessel damage does not appear to be caused by a specific component of cigarette smoke or e‑cigarette vapor.
Rather, it appears to be caused by airway irritation which triggers biological signals in the valgus nerve.
Dr Matthew Springer, a professor of medicine in the division of cardiology at the University of California, San Francisco said: ‘We were surprised to find that there was not a single component that you could remove to stop the damaging effect of smoke or vapors on the blood vessels.’
‘As long as there’s an irritant in the airway, blood vessel function may be impaired,’ he said.
‘This finding makes no sense whatsoever, suggesting this is an unreliable analysis and should not be trusted,’ he said.
‘Only e-cigarette users were included and what this likely means is that there is some important confounding variable that was not controlled.
‘It is a spurious finding that has little biological plausibility and is likely not replicated in other datasets, especially since this finding is only seen with the problematic outcome of foetus death and not the more reliable outcome of high risk birth.’
He added, however, that the topic of vaping harms in pregnancy was still an important one and deserving of more research.
For expectant mums with a nicotine habit wanting to help keep their baby safe, Professor Shahab recommended using licensed products like patches and gum in the first instance.
‘But if you find using an e-cigarette helpful for quitting and staying smoke-free, it’s much safer for you and your baby than continuing to smoke,’ he said.
Hazel Cheeseman, deputy chief executive from the health charity Action on Smoking and Health, said pregnant women struggling to quit traditional tobacco products should not be put off using vapes to help.
‘Many women in the UK are successfully using vapes to avoid smoking in pregnancy,’ she said.
‘It is irresponsible to discourage them from doing so without clear evidence of harm given the known and very substantial risks to mother and baby from smoking in pregnancy.’
The NHS says little research has been done into the safety of vaping in pregnancy and particularly if the vapour is harmful to a developing baby.
But the prestigious Mayo Clinic in the US warns that the nicotine contained in electronic can permanently damage a baby’s developing brain and other organs, alongside many of the other chemicals in the devices.
Using a vape as smoking cessation aid while pregnant is not officially recommended by the MHS which advises expectant mums struggling to quit to use patches or gums instead.
While vapes are generally accepted as being healthier than cigarettes, experts are still unsure if there could be a long-term health cost of using the devices.
A King’s College London study, commissioned by the Office for Health Improvement and Disparities at the Department of Health, has said it was clear that vaping is less harmful than cigarettes in the short to medium term and smokers should be encouraged to switch to vapes.
However, it said current research is not robust enough to make clear conclusions about how harmful vaping is in the longer term.
Vapes use has soared in the UK in recent years, with users blowing plumes of smoke across the country and vape shops becoming a common fixture on almost every High Street.
But the rise of the vape has not been without controversy, given the fact they can cost as little as £5 and their popularity with children.
Earlier this month major retailers pulled sales of bestselling Elf Bar vapes after a Mail investigation found the company was breaking the law on nicotine limits.
Tesco, Sainsbury’s and WH Smith withdrew all Elf Bar’s products and Morrisons and Asda stripped the top-ranked Elf Bar 600 range from their shelves.
It came after independent lab tests commissioned by the Mail found the 600 line of e-cigarettes were at least 50 per cent over the legal limit for nicotine e-liquid.
Last September, experts called for a crackdown on the sale of vapes to children and concluded little is known about the long-term impact of e-cigarettes on health.