Pregnant women are being warned about the dangers of using e-cigarettes after a new study says it can lead to an increased risk of asthma in children.
Vaping and E-cigarettes are often seen as a safer option to smoking, but this latest research has called that into question.
The study by researchers at the University of Technology in Australia exposed pregnant mice to vaping, with and without nicotine.
It found it increased the risk of the mice developing asthma in their offspring.
The lead researcher says it shows using e-cigarettes during pregnancy is dangerous and action is needed to remove the view that they are safe.
Dr Pawan Sharma, Chancellors Fellow and Research Leader in the Airways Disease Group at the University of Technology Sydney, Australia, said: "These findings highlight that e-cigarette use during pregnancy should not be considered safe."
"Our study found that maternal vaping increased the risk and severity of allergic asthma in offspring. We also found that the detrimental effects of vaping were partially mediated through impairment of mitochondrial function, which affects cellular respiration, and were independent of nicotine.
"This means that vaping, even without nicotine present, has a demonstrated negative impact on cell function."
The Irish Cancer Society believes pregnant women should not smoke or vape.
Head of Services, Donal Buggy, said: "It's not easy to quit smoking, but there is help out there to help people quit smoking.
"The best thing that you can do for your child is to quit smoking during pregnancy."
However, the Irish Vape Vendors Association is criticising the research, saying vaping is a safer alternative to smoking, and that all the study shows is that pregnant mice should not vape.
Their spokesperson, Gillian Golden, said: "What some of these mice studies do is they subject the mouse model, or even some mouse cells, to far more exposure of vapour than a human would ever get.
"A lot of these media headlines can cause stress in a vaper, so that they may think they may be better off smoking because vaping is no better for them.
"That's not the case. We know and we have the proof and the evidence that vaping is 95% safer than smoking."