A Preconception Cohort Study of Nicotine Vaping and Incidence of Spontaneous Abortion

We evaluated association of preconception nicotine vaping among female and male partners with spontaneous abortion (SAB) incidence, and the extent to which associations vary by cigarette smoking.

In a prospective cohort study, 6136 participants assigned female-at-birth and 1688 of their partners assigned male-at-birth reported preconception nicotine vaping and cigarette smoking via online questionnaire. Female partners reported incident pregnancies and outcomes (e.g., SAB) on follow-up questionnaires completed every 8 weeks and in early and late pregnancy. We used multivariable Cox proportional hazards regression models estimated adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) for association between vaping and SAB incidence, overall and by smoking history.

Mean age was 30 and 32 for females and males respectively. Among females, 13% reported ever-vaping and 14% reported ever-smoking, while 19% of males reported ever-vaping and 24% reported ever-smoking. Relative to female never-vapers, aHRs were 1.03 for former vaping (95% CI 0.86-1.24) and 0.91 for current vaping (95% CI 0.61-1.36). Former and current vaping were also not appreciably associated with SAB rate among ever-smokers. In the couple-based cohort, relative to male never-vapers, aHRs were 1.00 for male former-vapers (95% CI: 0.74-1.35) and 0.67 for male current-vapers (95% CI: 0.35-1.25). Additional analysis of female participants after stratifying by finer categories of smoking status did not identify any meaningful association with SAB incidence.

The current study found that vaping in either partner during the preconception period was not associated with SAB incidence. Cigarette smoking also did not modify this association.

The rising prevalence of vaping invokes greater scrutiny on its possible adverse reproductive effects. Studies have linked vaping to adverse birth events, and clear guidance is made to avoid vaping in pregnant people. However, guidance about vaping during preconception is less clear despite research showing how preconception behaviors are linked to adverse pregnancies and birth outcomes. Our cohort study finds little association between preconception vaping and spontaneous abortion. In context of established risks of vaping on fetal outcomes, this study highlights the need for additional evidence-based information about preconception vaping to help couples make lifestyle decisions for optimal reproductive outcomes.