Switching from tobacco cigarettes in very early pregnancy: The effects of in utero e-cigarette exposure on mouse offspring neurodevelopment and behaviour

Introduction: Electronic cigarettes (e-cigarettes) are often perceived to be safer than smoking, which has led to some women switching to e-cigarettes during pregnancy. However, the effects of switching from smoking to e-cigarettes on both pregnancy outcomes and the foetus are largely unknown. This study aimed to investigate the effects of switching from tobacco smoking to e-cigarette use in very early pregnancy on birth outcomes, neu-rodevelopment and behaviour of the offspring.Methods: Female BALB/c mice were exposed to cigarette smoke for up to two weeks before being mated. Mated dams were then allocated to one of four treatment groups: (i) continued exposure to cigarette smoke (ii) exposure to e-cigarette aerosol with nicotine, (iii) or without nicotine, or (iv) medical air. Pregnant mice were exposed for 2 h per day for the duration of pregnancy. Gestational outcomes including litter size and sex ratio were assessed, in addition to early-life markers of physical-and neuro-development. At 8 weeks of age, motor coordination, anxiety, locomotion, memory and learning of the adult offspring were assessed.Results: Gestational outcomes and early markers of physical-and neuro-development were unaffected by in utero exposure, as well as locomotion, anxiety-like behaviour, and object recognition memory during adulthood. However, both e-cigarette groups displayed increased spatial recognition memory compared to air exposed controls. Maternal exposure to nicotine containing e-cigarette aerosol was found to increase offspring body-weight and impair motor skill learning.Conclusions: These results suggest there may be some benefits as well as negative effects of switching to e-cig-arettes in early pregnancy.

Automated summary

This study aimed to investigate the effects of switching from tobacco smoking to e-cigarette use in very early pregnancy on birth outcomes, neurodevelopment, and behavior of the offspring. The results showed that in utero exposure to e-cigarette aerosol did not have negative effects on gestational outcomes and early markers of physical and neurodevelopment. However, maternal exposure to nicotine-containing e-cigarette aerosol increased offspring body weight and impaired motor skill learning.