Exposure of pregnant mice to e-cigarette vapor impairs lung function in their offspring

One study observed impaired lung function, with signs of fibrosis and mucus hypersecretion in mice exposed in utero to e-cigarette vapors, with or without nicotine. In addition, an increase in body mass was also observed in females as adults.

Several animal studies on the effects of in utero exposure to e-cigarette vapors have suggested an impact on cardiovascular functions, the occurrence of pulmonary inflammation, with alteration of the fetal lung structure. The study published by a team of researchers from Ohio focuses on lung function and structure.[1].

Damage to lung function and structure

In this study, mice were exposed to e-cigarette vapors during the three weeks of gestation, for four hours per day, five days per week. The effects on the lungs of the offspring of these mice were examined at 5 months of age.

The researchers observed a deterioration in lung function in the descendants of the exposed mice, whether or not the e-liquid contained nicotine. They observed signs of fibrosis in the lungs, airways and blood vessels, which can alter the elasticity of the lungs. Mucus secretion was also increased, which contributes to blocking the airways. Finally, an increase in weight was noted in female mice once adults, while their birth weight was normal.

The authors attribute these consequences to exposure to particles containing acetone, acetaldehyde and in particular formaldehyde emitted during the degradation of propylene glycol during vaporization. However, they remain cautious about these observations and call for extending this study, as the number of mice is small.

Advice for pregnant women

The transposition of animal studies to humans is a recurring subject of debate. This argument was notably raised by the tobacco industry in the 1950s, following the first research highlighting a link between tobacco and cancer.[2]However, studies conducted on animals often constitute an experimental basis which can serve as a prelude to observations in humans.

As a precaution, the authors advise avoiding any consumption or exposure to e-cigarette vapors during pregnancy. A position corresponding to that supported by the US Centers for Disease Control and Prevention (CDC), which noted that 7% of American women vaped during their pregnancy.[3]. The British approach to harm reduction, echoed by vaping supporters[4], recommends the use of electronic cigarettes during pregnancy to avoid returning to smoking, while the safety of taking nicotine in the form of nicotine replacement therapy (NRT) – patches, gum, lozenges, etc. – allows them to be taken during pregnancy. Overall, the possible toxicity of electronic cigarette vapors requires caution and their use is not recommended for pregnant women.

Keywords: pregnancy, lungs, electronic cigarette, long term, mouse

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  [1] Aslaner D, Alghothani O, Saldana T, Ezell K, Yallourakis M, MacKenzie D, Miller R, Wold L, Gorr M. E-cigarette vapor exposure in utero causes long-term pulmonary effects in offspring. Am J Physiol Lung Cell Mol Physiol 323: L676–L682, 2022. [2] Proctor R, Golden Holocaust, The Tobacco Industry Conspiracy, Paris, Ed. Equateurs, 2014, p. 208-219. [3] Gibbs K, Collaco JM, McGrath-Morrow SA. Impact of tobacco smoke and nicotine exposure on lung development. Chest 149: 552–561, 2016. [4] Pregnancy and vaping, Sovape, published June 24, 2020, consulted December 9, 2022. National Committee Against Smoking |