Vaping Could Damage Female Fertility
Vaping, or the use of e-cigarettes, is a growing trend but little is known about its effects on health. In a new study published in the Journal of the Endocrine Society, scientists have found that vaping could have harmful effects on the health of female mice, specifically affecting their fertility and the health of their offspring [1. Wetendorf M, Randall LT, Lemma MT, Hurr SH, Pawlak JB, Tarran R, Doerschuk CM, Caron KM. E-cigarette exposure delays implantation and causes reduced weight gain within in utero exposed female offspring. Journal of the Endocrine Society. 2019].
What is the difference between e-cigarettes and traditional tobacco cigarettes?
The dangerous effects of smoking traditional tobacco cigarettes are well known. As well as the obvious harmful effects on the lungs in the form of diseases such as COPD (Chronic Obstructive Pulmonary Disease), smoking is responsible for causing a long list of cancers and cardiovascular diseases. Smoking results in 78,000 deaths per year in the UK and many more people are left with lifelong disabilities as a result of the habit.
Furthermore, numerous studies have shown how smoking traditional cigarettes can be particularly damaging for fertility. Smoking drastically reduces fertility in both men and women, and smoking whilst pregnant is particularly dangerous. This is because it is extremely harmful for the health of the growing baby, and it increases the risk of miscarriage.
E-cigarettes are seen as a healthier option compared to traditional tobacco cigarettes because e-cigarettes do not produce carbon monoxide and tar. These are two of the most toxic substances produced by traditional cigarettes, which are responsible for many of the health implications of smoking.
E-cigarettes contain a liquid which consists of a number of chemicals including nicotine. This is the component which makes cigarettes so addictive, but it is not actually as harmful as the other components of cigarettes. The other substances in e-cigarettes are propylene glycol, vegetable glycerine and flavourings. This is heated up to produce a vapour which is breathed in.
E-cigarettes are generally seen as being healthier than traditional cigarettes
The general consensus is that e-cigarettes are much less harmful than traditional cigarettes. An independent health review judged e-cigarettes to be 95% safer than traditional tobacco cigarettes.
Because of the lack of toxic chemicals, e-cigarettes are used to help smokers quit. Even for pregnant women, health professionals recommend vaping over smoking cigarettes, although the ideal option is to stop smoking altogether.
But the problem is that vaping is a relatively new phenomenon. Therefore the scientific research on its effects is sparse, particularly in terms of its long term impacts on health and how it can affect the developing baby in pregnancy.
E-cigarettes are also commonly used among young people of a reproductive age. The range of flavours available appeal to teenagers specifically, and there is a risk that vaping encourages younger people to become addicted to nicotine which can damage the developing brain.
A large number of pregnant women and young people use e-cigarettes worldwide. Therefore this new study from the University of North Carolina is particularly important in helping us to understand how safe vaping really is, in relation to fertility.
What happened in the new study?
Dr Caron and her team at the University of North Carolina studied the effects of e-cigarettes on fertility and the health of offspring using a mouse model. The scientists exposed mice to e-cigarette aerosols for four months.
They then measured the hormone levels of the mice, including the levels of a substance called progesterone which is important for maintaining a pregnancy. They also thoroughly examined the reproductive tissues of the mice using a microscope.
What were the results of the study?
The team found that vaping may delay pregnancy
The scientists found that when female mice were exposed to e-cigarettes before they conceived, this delayed their pregnancy. The team found that vaping specifically affected implantation, which is the process by which a fertilised embryo attaches to the lining of the wall of the uterus in females. However the process of fertilisation, when a sperm and egg cell come together, was not affected by vaping.
In particular, the team found that the first-time pregnancies of the mice were delayed. They also found that foetal survival may be affected by vaping before conception.
More research is needed to confirm these relationships and explain how they arise, but it is likely that vaping affects the transport of ions and signalling pathways which control the uterine environment. But it is also important to note that the effects in this study were slight.
However it is difficult to predict how these results will vary in humans. This is because certain genetic mutations, pre-existing health problems and environmental factors could potentially increase the effect that vaping has on fertility in the wider population.
The team discovered that vaping during pregnancy can be harmful to the offspring
Dr Caron and her team also found that vaping resulted in some harmful effects on the offspring of the mice which were exposed to e-cigarette vapours. However the effects were different according to the gender of the offspring.
For the male offspring of the mice, the effects of vaping were minimal. The team found that there was only a slight reduction in the fertility of the male offspring. However it remains to be seen whether this effect could be more meaningful in humans, where genetic and environmental factors could potentially exacerbate the impact of vaping on male fertility.
In the female offspring of the mice, the effects of vaping were more significant. This is because vaping affected the weight of the offspring, which was normal at the time of birth. However at 8.5 months old, the weight of the female offspring was significantly lower than the control mice which were not exposed to e-cigarette vapour in utero.
This showed that vaping affected the long-term health and metabolism of the female offspring of the mice, which could have important implications for humans. This is because vaping may exacerbate health conditions relating to metabolism and body weight in people who are already genetically predisposed to these.
Vaping has become a major concern in recent months
The US authorities have reported some worrying statistics
There has been a great deal of publicity surrounding vaping recently because authorities have linked vaping to 18 deaths in the USA. The youngest person affected was only 20 years old, and the average age of people who died from vaping-related illnesses was 50 years old.
In addition to this, vaping is the cause of 1,000 cases of a specific lung disease in the USA, and this particular condition is not fully understood. The symptoms of this disease develop slowly and consist of coughing, shortness of breath, pneumonia, fever, fatigue, chest pain and respiratory failure.
The effects of vaping are so worrying that some states including Massachusetts and New York have banned the sale of vaping products until there is more information available about how it affects health. Walmart has also announced that it will stop selling e-cigarettes in the US. Furthermore other countries have taken action, with India banning the production, import and sale of e-cigarettes.
What is behind the damaging effects of vaping?
The US health authorities are still investigating the deaths and diseases linked to vaping. The lung disease related to vaping is thought to have been caused by a contaminant potentially resulting in an immune reaction or chemical irritation, but this theory is still being examined.
There is also a great deal of suspicion surrounding the vaping oils in particular. Scientists believe that products which contain marijuana-related chemicals such as THC and vitamin E carry a higher risk of health problems.
Another area of concern is the thickeners which are added to vaping liquids, as these could potentially be damaging to health. Additionally if the vaping fluid is homemade or not purchased from a reputable supplier, there is a far greater chance of harm.
Is the same problem occurring in the UK?
Around 3.6 million people in the UK use e-cigarettes. However the health problems reported in the US are not occurring on the same scale in the UK because all the e-cigarette products are more tightly regulated by the Medicines and Healthcare Products Regulatory Agency (MHRA).
The agency operates a ‘Yellow Card’ report system through which people using e-cigarettes can report any adverse effects. But worryingly, there have been 74 separate Yellow Card reports filed to the MHRA by both healthcare professionals and members of the public.
Vaping in the UK is not risk-free, and there have been high profile cases of UK patients developing health problems due to vaping. In the British Medical Journal last year, doctors reported the case of a 34 year old woman who developed lipoid pneumonia as a result of vaping. They determined that this was specifically due to the vegetable glycerine found in e-cigarettes [2. Viswam D, Trotter S, Burge PS, Walters GI. Respiratory failure caused by lipoid pneumonia from vaping e-cigarettes. BMJ Case Reports. 2018].
Scientists and governmental agencies are currently investigating the effects of vaping for UK consumers. The general consensus is that vaping is still a safer option than smoking traditional cigarettes, but vaping is likely to bring its own risks which we are still in the process of uncovering.
What should I do now?
For now, it is best to avoid using e-cigarettes until more information is known about their health effects. But also be sure to avoid using traditional cigarettes, as the dangerous effects of these are already well documented.
If you really do have to use e-cigarettes, make sure that you buy them from a reputable and well-known supplier. Also make sure you avoid using vaping fluid containing any cannabis products or synthetic cannabinoids such as ‘spice’.
Vaping advice video
This study shows that important progress has been made in determining the effects of vaping and how safe it really is as an alternative to traditional tobacco cigarettes. However as this study has been conducted on mice, a great deal more research is needed to determine the health implications of vaping in a human population, particularly in relation to fertility and the health of the developing baby in pregnancy.
It is clear that vaping is significantly safer than traditional cigarette smoking, but it is important to remember that e-cigarettes are not completely free of risk. The healthiest option of all is quitting altogether. This will drastically improve your fertility and your general health and wellbeing.
For more support on how to quit vaping or smoking, please visit your GP. You can also access support online here.
Dr. Kooner is Deputy Director of The Advanced Fertility Center of Chicago and has been a Specialist in Fertility Treatment since 1999.
As well as the areas that the clinic specialises in general, he is particularly interested in managing oocyte donation, female same-sex couples, single women having sperm donation and those considering egg freezing.
Dr. Kooner regularly speaks at fertility meetings. He has published in national journals and constantly contributes to the fertility research and publications from Advanced Fertility Center of Chicago.