Pregnant women who use e-cigs may be harming their unborn babies, new research shows.
US tests suggest vaping damages the foetus’s nervous system, making it as harmful as smoking tobacco.
Scientists found it can lead to poorer learning, memory and co-ordination and a rise in hyperactive behaviour.
It may also reduce a newborn’s sperm count and damage sperm DNA.
Two million Brits use e-cigs because they are seen as “safe”.
UK health officials even encourage smokers to switch to vaping. The alarming new risks were presented to the American Association for the Advancement of Science in Washington.
Lead researcher Prof Judith Zelikoff said the findings illustrated for the first time the potential danger to the unborn child.
“What it shows is that there is certainly some concern over the safety of e-cigarettes, particularly in relation to pregnant women or young infants,” she said.
“There are potential dangers revealed by these studies indicating a possible impact to the unborn child that may be seen at birth but may occur later in the life of the child.
“The perception is that e-cigarettes are completely safe for pregnant women and vulnerable groups like infants, but we can’t say that. This is groundbreaking research.”
She added: “Are they safer than cigarettes? The answer’s not there but they don’t appear to be.
“One has to assume that these products are not safe for this particular population.
“Our studies should give pause to people who are pregnant and using these products as an alternative.”
Her studies on mice show that – just like cigarette smoke – vaping chemicals disrupt gene activity in the part the brain
responsible for higher mental functions.
And even e-cig vapour without nicotine caused a large number of gene changes.
She concluded: “While more studies are needed to better understand these effects, these translational studies suggest that early life exposure to alternative tobacco/nicotine products can adversely affect reproduction, development and long term health.”
Two major components in e-cigarettes are propylene glycol and vegetable glycerin. Flavourings can also be added.
E-cigarettes vaporise nicotine to provide a smoker’s hit without the risk of tar and other cancerous chemicals.
Public Health England, the government’s public health agency, has insisted vaping is 95% safer than tobacco and could help millions of smokers kick the habit.
Last summer, officials recommended that e-cigarettes be prescribed on the NHS as soon as possible.
E-Voke, the e-cigarette produced by British American Tobacco, has now been approved by the Medicines and Healthcare Products Regulatory Agency to be marketed for “smoking cessation”.
An MHRA spokesman confirmed: “We have recently licensed the e-Voke as a medicine, which means it is a product of acceptable quality and can be an effective aid to smoking cessation.”
One in eight pregnant women in the UK continue smoking regular cigarettes.
Prof Zelikoff added: “Women may be turning to these products as an alternative because they think they’re safe. Well, they’re not.
“Our findings should open people’s eyes by showing that this is something that potentially can be harmful if used during pregnancy.
“It should lead to much more research – this is just the beginning.”
Prof Adam Balen, chairman of the British Fertility Society, said: “Whilst e-cigarettes may help some people to stop smoking real cigarettes, one cannot escape the reality that various chemicals are still being inhaled that have potentially harmful effects both to health, fertility and also the non-consenting participant, that is the baby.
“It may therefore be wrong to switch during pregnancy and best to avoid all kinds of smoking.”
Dr Patrick O’Brien, of the Royal College of Obstetricians and Gynaecologists , said that although e-cigarettes had become a “popular alternative” to regular cigarettes, he would “not recommend” them to pregnant women.
He added: “Smoking cigarettes and breathing in second-hand smoke during pregnancy is unequivocally harmful to both the mother and growing baby,
including increasing risk of miscarriage, stillbirth, and sudden infant death syndrome.
“Smoking can affect the baby’s growth and health with effects such as asthma continuing into adult life.
“Pregnant women and their families should be encouraged and supported to stop smoking.
“Nicotine replacement therapy can help some people quit and is free on the NHS for pregnant women.
“E-cigarettes are becoming a popular alternative to tobacco smoking, but at the moment what is in them is not controlled and some have been found to contain harmful substances as well as nicotine, as this study in mice demonstrates.
“As the long-term risks for the developing baby from using them are not known, we do not recommend women use these products in pregnancy.
“Women who want help giving up smoking should talk to their GP, midwife or stop smoking advisor for more information.”
Tom Pruen, chief scientific officer of the Electronic Cigarette Industry Trade Association, which represents e-cigarette firms, insisted e-cigarettes were still “likely to be better” for pregnant women than smoking.
He said: “It has long been known that nicotine crosses the placental barrier, and can have negative effects on the developing foetus.
“However, the impact of nicotine is often associated with the impact of smoking, which is much more significant.
“As a result of this, it is best to avoid nicotine use during pregnancy, but it is more important to avoid smoking.”
On e-cigarettes, he added: “Ideally, they shouldn’t be used during pregnancy, but using them is likely to be better than smoking. E-cigarettes are also available without nicotine, which might provide an alternative solution for some.”
But Prof Zelikoff warned: “We have to make people more aware of the risks. The major point is that these e-cigarettes need more safety testing.
“Animal studies suggest there may be neurological changes as a result of early-life exposure and they appear to be similar to those from early-life exposure to cigarette smoke.
“Definitely more research needs to be done in this area. The public should be aware that there hasn’t been a sufficient number of scientific studies on these products.”
She also raised concerns about the idea e-cigarettes helped smokers quit tobacco.
Prof Zelikoff added: “Many people who use e-cigarettes are dual users. They enjoy e-cigarettes and they smoke.
“And e-cigarettes can be a gateway – there are concerns that adolescents are starting with e-cigarettes and going onto real cigarettes.”