Perceptions and use of electronic cigarettes in pregnancy

Prevalence of Cigarette Smoking, E-cigarette Use, and Dual Use Among Urban and Rural Women During the Peripartum Period, PRAMS 2015-2020

OBJECTIVES

Evidence has emerged on the health dangers of electronic cigarette (e-cigarette) use among pregnant women and neonates. We examined whether rural residence is a risk factor for smoking and e-cigarette use among women during the peripartum period in the United States.

METHODS

This study was based on pooled cross-sectional 2015-2020 data from the Pregnancy Risk Assessment Monitoring System. The outcome was exclusive smoking, exclusive e-cigarette use, and use of both products (ie, dual use) versus use of neither tobacco product by women with live infants aged 2 to 6 months. We examined rural-urban differences in outcome by using univariate and multivariable multinomial logistic regressions with post hoc contrasts and marginal analyses, adjusting for complex survey design and nonresponse.

RESULTS

During the peripartum period, 5.0% of women were smoking combustible cigarettes, 5.0% were using e-cigarettes, and 1.9% were using both tobacco products. The crude prevalence of e-cigarette use was 1.1 percentage point higher, and the adjusted prevalence was 0.8 percentage points lower for rural versus urban women (P < .001 for both). Among rural women, 6.7% (95% CI, 6.3%-7.1%) smoked combustible cigarettes exclusively and 2.6% (95% CI, 2.3%-2.8%) used both products, as compared with 4.5% (95% CI, 4.4%-4.8%) and 1.7% (95% CI, 1.6%-1.8%) of urban women, respectively, adjusting for sociodemographic and health-related characteristics.

CONCLUSIONS

Maternal sociodemographic and health-related characteristics differed by combustible smoking versus e-cigarette use during the peripartum period. The effect of residence on e-cigarette use was significantly confounded by sociodemographic and health-related characteristics, resulting in clinically comparable prevalence of e-cigarette use in rural and urban mothers with live infants aged 2 to 6 months.

Electronic cigarette use during pregnancy and the risk of adverse birth outcomes: A cross-sectional surveillance study of the US Pregnancy Risk Assessment Monitoring System (PRAMS) population

BACKGROUND

Research on health effects and potential harms of electronic cigarette (EC) use during pregnancy is limited. We sought to determine the risks of pregnancy EC use on pregnancy-related adverse birth outcomes and assess whether quitting ECs reduces the risks.

METHODS

Women with singleton live births who participated in the US Pregnancy Risk Assessment Monitoring System (PRAMS) survey study 2016-2020 were classified into four mutually exclusive groups, by their use of ECs and combustible cigarettes (CCs) during pregnancy: non-use, EC only use, CC only use, and dual use. We determined the risk of preterm birth, low birth weight, and small-for-gestational-age (SGA) by comparing cigarette users to non-users with a modified Poisson regression model adjusting for covariates. In a subset of women who all used ECs prior to pregnancy, we determined whether quitting EC use reduces the risk of preterm birth, low birth weight, and SGA by comparing to those who continued its use. All analyses were weighted to account for the PRAMS survey design and non-response rate.

RESULTS

Of the 190,707 women (weighted N = 10,202,413) included, 92.1% reported cigarette non-use, 0.5% EC only use, 6.7% CC only use, and 0.7% dual use during pregnancy. Compared with non-use, EC only use was associated with a significantly increased risk of preterm birth (adjusted risk ratio [aRR]: 1.29, 95% confidence interval [CI]: 1.00, 1.65) and low birth weight (aRR: 1.38, 95%CI: 1.09, 1.75), but not SGA (aRR: 1.04, 95%CI: 0.76, 1.44). Among 7,877 (weighted N = 422,533) women EC users, quitting use was associated with a significantly reduced risk of low birth weight (aRR: 0.76, 95%CI: 0.62, 0.94) and SGA (aRR: 0.77, 95%CI: 0.62, 0.94) compared to those who continued to use ECs during pregnancy.

CONCLUSIONS

Pregnancy EC use, by itself or dual use with CC, is associated with preterm birth and low birth weight. Quitting use reduces that risk. ECs should not be considered as a safe alternative nor a viable gestational smoking cessation strategy.

Investigating Behavioral and Neuronal Changes in Adolescent Mice Following Prenatal Exposure to Electronic Cigarette (E-Cigarette) Vapor Containing Nicotine

A substantial percentage of pregnant smokers stop using traditional cigarettes and switch to alternative nicotine-related products such as e-cigarettes. Prenatal exposure to tobacco increases the risk of psychiatric disorders in children. Adolescence is a complex phase in which higher cognitive and emotional processes undergo maturation and refinement. In this study, we examined the behavioral and molecular effects of first-trimester prenatal exposure to e-cigarettes. Adult female mice were divided into normal air, vehicle, and 2.5%-nicotine-exposed groups. Our analyses indicated that the adolescents in the 2.5%-nicotine-exposed group exhibited a significant lack of normal digging behavior, elevated initial sucrose intake, and reduced recognition memory. Importantly, we identified a substantial level of nicotine self-administration in the 2.5%-nicotine-exposed group. At a molecular level, the mRNAs of metabotropic glutamate receptors and transporters in the nucleus accumbens were not altered. This previously undescribed work indicates that prenatal exposure to e-cigarettes might increase the risk of nicotine addiction during adolescence, reduce cognitive capacity, and alter normal adolescent behavior. The outcome will aid in translating research and assist healthcare practitioners in tackling addiction and mental issues caused by toxicological exposure. Further, it will inform relevant policymaking, such as recommended taxation, labeling e-cigarette devices with more detailed neurotoxic effects, and preventing their sale to pregnant women and adolescents.

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, neurodevelopment 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 bodyweight and impair motor skill learning.

CONCLUSIONS

These results suggest there may be some benefits as well as negative effects of switching to e-cigarettes in early pregnancy.

Participatory research on the prevalence of Multi-Substance vaping in college students

OBJECTIVES

To assess electronic nicotine delivery system (ENDS) use and vaping behaviors and attitudes in college students.

METHODS

A student-faculty partnership administered a cross-sectional survey to undergraduate students (N = 339) in 2019.

RESULTS

49.8% of students reported using ENDS or vaping in the past 30 days. 48.9% of students who vaped reported vaping more than one substance in the past 30 days. The most commonly vaped substances were cannabis (34.9%), nicotine (26.7%), and flavor (19.2%). Reasons for initiating ENDS use were social (64.8%), for the high (40.8%), and for the flavor (32.4%). Both users and non-users believed ENDS were harmful and favored regulation.

CONCLUSIONS

Young people who use ENDS commonly vape more than one substance; a critical finding in light of the current vaping lung injury epidemic. The importance of social reasons for initiating ENDS and broad support for regulation suggest jurisdictions consider regulation to reduce ENDS use in young adults.

Electronic Cigarette Use during Pregnancy: Is It Harmful?

Although combustible cigarette smoking rates have declined in recent years, alternative tobacco product use, particularly electronic cigarette use ("vaping"), has increased among young adults. Recent studies indicate that vaping during pregnancy is on the rise, possibly due to the perception that it is a safer alternative to combustible cigarette smoking. However, e-cigarette aerosols may contain several newer, potentially toxic compounds, including some known developmental toxicants that may adversely impact both the mother and the fetus. However, there is paucity of studies that have examined the effects of vaping during pregnancy. While the adverse perinatal outcomes of cigarette smoking during pregnancy are well established, the specific risks associated with inhaling vaping aerosols during pregnancy requires more research. In this article, we discuss the existing evidence and knowledge gaps on the risks of vaping during pregnancy. Studies that investigate vaping-associated systemic exposure and its effects (i.e., biomarker analyses) and maternal and neonatal clinical health outcomes are needed to reach more robust conclusions. We particularly emphasize the need to go beyond comparative studies with cigarettes, and advocate for research that objectively evaluates the safety of e-cigarettes and other alternative tobacco products.

Maternal e-cigarette use can disrupt postnatal blood-brain barrier (BBB) integrity and deteriorates motor, learning and memory function: influence of sex and age

Electronic nicotine delivery systems (ENDS), also commonly known as electronic cigarettes (e-cigs) are considered in most cases as a safer alternative to tobacco smoking and therefore have become extremely popular among all age groups and sex. It is estimated that up to 15% of pregnant women are now using e-cigs in the US which keeps increasing at an alarming rate. Harmful effects of tobacco smoking during pregnancy are well documented for both pregnancy and postnatal health, however limited preclinical and clinical studies exist to evaluate the long-term effects of prenatal e-cig exposure on postnatal health. Therefore, the aim of our study is to evaluate the effect of maternal e-cig use on postnatal blood-brain barrier (BBB) integrity and behavioral outcomes of mice of varying age and sex. In this study, pregnant CD1 mice (E5) were exposed to e-Cig vapor (2.4% nicotine) until postnatal day (PD) 7. Weight of the offspring was measured at PD0, PD7, PD15, PD30, PD45, PD60 and PD90. The expression of structural elements of the BBB, tight junction proteins (ZO-1, claudin-5, occludin), astrocytes (GFAP), pericytes (PDGFRβ) and the basement membrane (laminin α1, laminin α4), neuron specific marker (NeuN), water channel protein (AQP4) and glucose transporter (GLUT1) were analyzed in both male and female offspring using western blot and immunofluorescence. Estrous cycle was recorded by vaginal cytology method. Long-term motor and cognitive functions were evaluated using open field test (OFT), novel object recognition test (NORT) and morris water maze test (MWMT) at adolescence (PD 40-45) and adult (PD 90-95) age. In our study, significantly reduced expression of tight junction proteins and astrocyte marker were observed in male and female offspring until PD 90 (P < 0.05). Additionally, prenatally e-cig exposed adolescent and adult offspring showed impaired locomotor, learning, and memory function compared to control offspring (P < 0.05). Our findings suggest that prenatal e-cig exposure induces long-term neurovascular changes of neonates by disrupting postnatal BBB integrity and worsening behavioral outcomes.

Birth Outcomes Associated With E-Cigarette and Non-E-Cigarette Tobacco Product Use During Pregnancy: An Examination of PATH Data Waves 1-5

OBJECTIVES

To examine associations of prenatal e-cigarette use to pregnancy and birth outcomes.

METHODS

Currently pregnant women (n = 1 037) from Waves 1 through 4 of the Population Assessment of Tobacco and Health Study who had pregnancy or live birth outcome data in a subsequent wave (Waves 2-5; 2013 to 2019). Weighted bivariate and multivariable models\ examined associations between past 30-day tobacco use assessed during pregnancy (any past 30-day e-cigarette use, any past 30-day non-e-cigarette tobacco use, or no past 30-day tobacco use) with adverse pregnancy (miscarriage, abortion, ectopic or tubal pregnancy, stillbirth) and birth outcomes (preterm birth, low birth weight, birth defect, placenta previa, placental abruption, pre-eclampsia) reported in the subsequent wave.

RESULTS

Approximately 1% of pregnant women reported past 30-day exclusive e-cigarette use and 3.2% used e-cigarettes and one other tobacco product. Compared to no tobacco use, past 30-day e-cigarette use (exclusive or use with another tobacco product) during pregnancy was not associated with increased odds of an adverse pregnancy or birth outcome in bivariate or multivariable models. Past 30-day non-e-cigarette tobacco use was associated with increased odds of an adverse pregnancy outcome in multivariable models, but not an adverse live birth outcome. Compared to past 30-day cigarette use, past 30-day e-cigarette use during pregnancy was not associated with lowered odds of a birth or pregnancy outcome.

CONCLUSIONS

E-cigarette use during pregnancy is rare. Understanding the positive and negative impacts of pre-natal e-cigarette use on women's health may guide public health messaging campaigns.

IMPLICATIONS

Results showed that past 30-day e-cigarette use during pregnancy was low, with cigarette smoking remaining the most prevalent form of tobacco use during pregnancy. Current e-cigarette use during pregnancy used either exclusively or with another tobacco product, was not associated with increased risk of an adverse pregnancy, or birth outcome. A small sample size of e-cigarette users and limited information on quantity and frequency of e-cigarette use before and during pregnancy may limit conclusions. Healthcare providers may use this information when discussing the harms and consequences associated with e-cigarette and tobacco use during pregnancy.

Passive exposure to electronic cigarette aerosol in pregnancy: A case study of a family

BACKGROUND

Passive exposure to the aerosols of electronic cigarettes (e-cigarettes) has been little studied. We assessed this exposure in late pregnancy in a woman and her 3-year-old child, exposed through e-cigarette use by another household member.

METHODS

This prospective longitudinal case study involved a family unit consisting of an e-cigarette user, a pregnant woman who delivered an infant during the study, and the couple's older 3-year-old son. At 31, 36, and 40 weeks of the pregnancy, we measured biomarkers (nicotine metabolites, tobacco-specific nitrosamines, propanediols, glycerol, and metals) in the urine and hair of all three participants and in the saliva of the adults, in cord blood at delivery, and in the breast milk at the postpartum period.

RESULTS

Samples from the e-cigarette user showed quantifiable concentrations of all analytes assessed (maximum urinary cotinine concentration, 4.9 ng/mL). Among samples taken from the mother, nicotine and its metabolites were found mainly in urine and also in saliva and hair, but not in cord blood. During the postpartum period, we found cotinine concentrations of 2.2 ng/mL in the mother's urine and 0.22 ng/mL in breast milk; 1,2-propanediol was generally detected in urine and saliva, but not in cord blood or breast milk. The maximum urinary cotinine concentration in the 3-year-old child was 2.6 ng/mL and propanediols also were detected in his urine. Nitrosamines were not detected in samples taken from the mother or the 3-year-old. Metals found in the refill liquid were detected at low levels in both the mother and the 3-year-old.

CONCLUSIONS

We detected low but not negligible concentrations of e-cigarette-related analytes (including cord blood and breast milk) in an exposed pregnant non-user and in a 3-year-old child also living in the home. Passive exposure to e-cigarette aerosols cannot be disregarded and should be assessed in larger observational studies.

Impact of Prenatal Nicotine Exposure on Placental Function and Respiratory Neural Network Development

Smoking during pregnancy is associated with multiple undesirable outcomes in infants, such as low birth weight, increased neonatal morbidity and mortality, and catastrophic conditions like sudden infant death syndrome (SIDS). Nicotine, the most addictive and teratogenic substance in tobacco smoke, reaches and crosses the placenta and can be accumulated in the amniotic fluid and distributed by fetal circulation, altering the cholinergic transmission by acting on the nicotinic acetylcholine receptors (nAChRs) expressed from very early gestational stages in the placenta and fetal tissue. Because nAChRs influence the establishment of feto-maternal circulation and the emergence of neuronal networks, prenatal nicotine exposure can lead to multiple alterations in newborns. In this mini-review, we discuss the undeniable effects of nicotine in the placenta and the respiratory neural network as examples of how prenatal nicotine and smoking exposition can affect brain development because dysfunction in this network is involved in SIDS etiology.

Exposure-response analysis of the association of maternal smoking and use of electronic cigarettes (vaping) in relation to preterm birth and small-for-gestational-age in a national US sample, 2016-2018

Introduction

The US experienced a surge in use of e-cigarettes. Smoking women may consider e-cigarettes during pregnancy as an alternative to smoking. E-cigarettes typically contain nicotine, an established cause of reduction in fetal growth in animal studies.

Methods

This cohort study included 99,201 mothers who delivered live singletons in 2016-2018 from the Pregnancy Risk Assessment Monitoring System. We created exposure categories based on self-reported number of cigarettes smoked per day and vaping frequency and evaluated their associations with preterm birth and small-for-gestational-age (SGA) birth (two established cigarette smoking-related risks).

Results

Dual users in late pregnancy were a heterogeneous group: 29% lightly smoked and occasionally vaped; 19% lightly smoked and frequently vaped; 36% heavily smoked and occasionally vaped; and 15% heavily smoked and frequently vaped. While dual users who heavily smoked and occasionally vaped had the highest adjusted OR for SGA (3.4, 95% CI 2.0, 5.7), all the dual users had, on average, about twice the odds of having SGA than non-users. While the risks of preterm birth were higher among sole light smokers (adjusted OR 1.3, 95% CI 1.1, 1.5) and sole heavy smokers (adjusted OR 1.5. 95% CI 1.2, 1.8) than non-users, the adjusted odds of preterm birth for dual users were not noticeably higher than those of non-users.

Conclusion

Relative to non-users, both smoking and vaping during pregnancy appear to increase risk of SGA, but excess risk of preterm birth appears to be primarily attributable to smoking alone. Higher levels of exposure tended to confer more risk.

Single-nucleus chromatin accessibility and RNA sequencing reveal impaired brain development in prenatally e-cigarette exposed neonatal rats

Although emerging evidence reveals that vaping alters the function of the central nervous system, the effects of maternal vaping on offspring brain development remain elusive. Using a well-established in utero exposure model, we performed single-nucleus ATAC-seq (snATAC-seq) and RNA sequencing (snRNA-seq) on prenatally e-cigarette-exposed rat brains. We found that maternal vaping distorted neuronal lineage differentiation in the neonatal brain by promoting excitatory neurons and inhibiting lateral ganglionic eminence-derived inhibitory neuronal differentiation. Moreover, maternal vaping disrupted calcium homeostasis, induced microglia cell death, and elevated susceptibility to cerebral ischemic injury in the developing brain of offspring. Our results suggest that the aberrant calcium signaling, diminished microglial population, and impaired microglia-neuron interaction may all contribute to the underlying mechanisms by which prenatal e-cigarette exposure impairs neonatal rat brain development. Our findings raise the concern that maternal vaping may cause adverse long-term brain damage to the offspring.

Impact of E-cig aerosol vaping on fetal and neonatal respiratory development and function

Electronic cigarette (e-cig) use has increased over the past decade, and exposure to e-cig aerosols during pregnancy raises concern for maternal and fetal health. The developing fetal lung is known to be sensitive to prenatal tobacco product exposure. Utilizing a 3-pronged approach, we examined the effects of prenatal e-cig aerosols with, and without nicotine on respiratory development in a murine model. RNAseq analysis of fetal lungs revealed extensive dysregulation in gene expression. Morphologic assessment of distal airspaces in neonatal lungs display an emphysematic phenotype. Respiratory mechanics of neonates display signs of increased respiratory workload, with increased resistance and decreased compliance. These data are novel and provide evidence that prenatal e-cig exposure may result in altered lung function or development of disease.

The effects of prenatal nicotine and THC E-cigarette exposure on motor development in rats

RATIONALE

In the USA, nicotine and cannabis are the most common licit and illicit drugs used among pregnant women. Importantly, nicotine and cannabis are now being combined for consumption via e-cigarettes, an increasingly popular delivery device. Both nicotine and tetrahydrocannabinol (THC), the primary psychoactive component of cannabis, cross the placenta barrier. However, the consequences of prenatal cannabis use are not well understood, and less is known about potential combination effects when consumed with nicotine, especially via e-cigarettes.

OBJECTIVE

The present study used a rodent model to examine how prenatal e-cigarette exposure to nicotine, THC, and the combination impacts motor development among offspring.

METHODS

Pregnant Sprague-Dawley rats were exposed to nicotine (36 mg/mL), THC (100 mg/mL), the combination, or vehicle via e-cigarette inhalation from gestational days (GD) 5-20. One sex pair per litter was tested on an early sensorimotor development task (postnatal days [PD] 12-20) and a parallel bar motor coordination task (PD 30-32).

RESULTS

Combined prenatal exposure to nicotine and THC delayed sensorimotor development, even though neither drug produced impairments on their own. In contrast, prenatal exposure to either nicotine or THC impaired motor coordination, whereas combined exposure exacerbated these effects, particularly among females.

CONCLUSIONS

These data illustrate that prenatal exposure to either nicotine or THC may alter motor development, and that the combination may produce more severe effects. These findings have important implications for pregnant women as we better understand the teratogenic effects of these drugs consumed via e-cigarettes.

Patterns and Trends in Use of Electronic Nicotine Delivery Systems Before and During Pregnancy: Pregnancy Risk Assessment Monitoring System, United States, 2016-2019

INTRODUCTION

This study used 2016-2019 Pregnancy Risk Assessment Monitoring System data to estimate prevalence of electronic nicotine delivery system (ENDS) use around pregnancy, changes in ENDS use and cigarette smoking from before to during pregnancy, and trends in these behaviors over time.

METHODS

ENDS and cigarette use during the 3 months before and the last three months of pregnancy were measured. Weighted prevalence estimates and 95% confidence intervals were estimated for outcomes overall and ENDS use by maternal characteristic for 2016-2019; logistic regression tested for differences in ENDS use by maternal characteristic and for linear trends in ENDS and cigarette use before and during pregnancy. Analyses were completed in 2021.

RESULTS

In 2019, 4.3% (N = 98,050) of women used ENDS before and 1.3% (N = 28,811) used ENDS during pregnancy. Most exclusive ENDS users (82.2%) and exclusive cigarette smokers (55.0%) stopped use during pregnancy. Among dual users, 46.3% stopped use during pregnancy while 20.2% continued dual use and 24.9% smoked cigarettes exclusively. Few dual users (8.6%) and exclusive cigarette smokers (0.5%) reported using ENDS exclusively during pregnancy. From 2016-2019, exclusive ENDS use increased and exclusive cigarette smoking decreased both before and during pregnancy.

CONCLUSIONS

ENDS use during pregnancy is low but increased since 2016. Less than one-half of dual ENDS and cigarettes users quit during pregnancy; few dual users or exclusive cigarette smokers switched to exclusive ENDS use during pregnancy. Continued surveillance of ENDS and other tobacco use during pregnancy is critical to inform public health activities that protect maternal and child health.

Cigarette smoking cessation and mental health treatment receipt in a U.S national sample of pregnant women with mental illness

OBJECTIVES

To (1) compare the probability of cigarette smoking cessation for pregnant women with and without past-year mental illness by the trimester of pregnancy; and (2) examine the association between the receipt of past-year mental health treatment and prenatal cigarette smoking cessation among pregnant lifetime-smokers with mental illness.

METHODS

We conducted secondary analysis of data from the National Survey on Drug Use and Health (NSDUH) 2008-2014. The NSDUH included 2019 pregnant lifetime smokers aged 18-44 years, 528 of whom had a mental illness. We used multiple logistic regression to model the probability of prenatal cigarette smoking cessation.

RESULTS

Pregnant lifetime-smokers with mental illness had a lower rate of cigarette smoking cessation than women without mental illness (47.9% vs. 61.7%, p = 0.001). Compared to pregnant women without mental illness, pregnant women with mental illness had a significantly lower odds of smoking cessation in the first trimester (Adjusted Odds Ratio [AOR]: 0.34, 95% Confidence Interval [CI]: 0.18-0.66), but not in the second (AOR: 0.87, 95% CI: 0.46-1.63) and third trimesters (AOR: 0.94, 95% CI: 0.51-1.72). The likelihood of quitting smoking did not differ significantly for pregnant lifetime-smokers with mental illness who received and did not receive mental health treatment (AOR: 1.69, 95% CI: 0.87-3.28).

CONCLUSION

Pregnant lifetime-smokers with mental illness are less likely to quit smoking than those without mental illness; overall, pregnant women tended to quit smoking as they progressed in their pregnancy. The receipt of mental health treatment was not associated with quitting smoking. Mental health care providers need to screen for cigarette use among pregnant women and strengthen smoking cessation efforts.

CLINICAL RELEVANCE

Pregnancy presents a unique opportunity for mental health care providers to screen for cigarette use in women with mental illness and support their smoking cessation efforts.

Effects of Prenatal Electronic Cigarette Exposure On Foetal Development: a Review of the Literature

Since their market launch in 2007, e-cigarettes gained popularity and were considered a relatively safe alternative to traditional cigarettes. Pregnant women and women of childbearing age in particular are increasingly turning to e-cigarettes. Little is known about the effects of prenatal exposure on the affected foetus. This paper aims to provide an overview of the current research on the effects of prenatal e-cigarette exposure on the foetus. Since studies in humans are lacking to date, this review refers only to animal and in vitro analyses. The PubMed and Web of Science databases were used for an extensive literature search. The search yielded N = 17 significant research papers. Possible sequelae resulting from prenatal exposure to traditional cigarettes were also seen in prenatal exposure to e-cigarettes. Prenatal e-cigarette exposure was found to be associated with increased DNA methylation overall, resulting in lower gene expression. This could adversely impact the development of affected children, especially in case of those genes relevant to their development. In mice, for example, this greatly reduced the cell vitality of neural and stem cells and increased cell death. Further, prenatal exposure to e-cigarettes resulted in numerous developmental disorders, such as malformations of facial morphology and lower birth weight. Moreover, in animal models the animals suffered from a deterioration of their short-term memory. Activity and cognitive flexibility increased, while anxiety behaviour decreased. It is clear that more research and especially studies of humans are needed on this issue. In addition, there is a need for more intense education of prenatal care professionals as well as women of childbearing age and during pregnancy.

DNA methylome perturbations: an epigenetic basis for the emergingly heritable neurodevelopmental abnormalities associated with maternal smoking and maternal nicotine exposure†

Maternal smoking during pregnancy is associated with an ensemble of neurodevelopmental consequences in children and therefore constitutes a pressing public health concern. Adding to this burden, contemporary epidemiological and especially animal model research suggests that grandmaternal smoking is similarly associated with neurodevelopmental abnormalities in grandchildren, indicative of intergenerational transmission of the neurodevelopmental impacts of maternal smoking. Probing the mechanistic bases of neurodevelopmental anomalies in the children of maternal smokers and the intergenerational transmission thereof, emerging research intimates that epigenetic changes, namely DNA methylome perturbations, are key factors. Altogether, these findings warrant future research to fully elucidate the etiology of neurodevelopmental impairments in the children and grandchildren of maternal smokers and underscore the clear potential thereof to benefit public health by informing the development and implementation of preventative measures, prophylactics, and treatments. To this end, the present review aims to encapsulate the burgeoning evidence linking maternal smoking to intergenerational epigenetic inheritance of neurodevelopmental abnormalities, to identify the strengths and weaknesses thereof, and to highlight areas of emphasis for future human and animal model research therein.

Electronic Nicotine Delivery Systems (ENDS) Use and Pregnancy II: Perinatal Outcomes Following ENDS Use During Pregnancy

Purpose of Review

This review examines the risk of adverse perinatal outcomes following electronic nicotine delivery system (ENDS) use during pregnancy, and considers whether there are sufficient data to support ENDS as a harm reduction approach during pregnancy.

Recent Findings

Seven papers assessed perinatal outcomes following ENDS use during pregnancy. There was evidence that ENDS use was associated with increased risk for some adverse perinatal outcomes (e.g., small for gestational age). However, the repeated use of data sets, insufficient data (e.g., timing of ENDS use, type of ENDS products used), and limited samples size, contributed to mixed findings on the degree to which ENDS use (alone or in combination with combustible cigarettes (CC)) impacts the risk of adverse perinatal outcomes relative to CC smoking alone.

Summary

The current data are still insufficient to support ENDS as a harm reduction approach, though findings do warrant concern and more detailed investigation of ENDS use during pregnancy. Future research directions, as well as implications for clinical recommendations and tobacco regulatory science are discussed.

Prenatal nicotine exposure was associated with long-term impact on the cardiovascular system and regulation-Review

AIM

The aim of this structured review was to discuss knowledge of nicotine use during pregnancy and long-term effects on children's cardiovascular function.

METHODS

PubMed and MEDLINE were searched for original papers that covered various forms of nicotine exposure during pregnancy and this identified 314 papers published in English from inception of the databases to 1 March 2021. The research focus was prenatal exposure that had long-term effects on the cardiovascular system. The search was expanded from the reference list of the selected papers, which identified another 17 papers.

RESULTS

The 34 original papers that were included covered 172,696 subjects from foetuses to 19 years of age. Cardiovascular autonomic dysfunction was discussed in 12 of the papers and 16 studies reported on blood pressure. The remaining studies covered structural or functional changes in arterial wall or heart. There were convincing data on autonomic dysfunction and increased blood pressure. Some data were conflicting and problems with misclassification of exposure were evident.

CONCLUSION

Prenatal nicotine exposure was associated with long-term developmental changes in the cardiovascular system and regulation. There were no safe periods, doses or nicotine products during pregnancy and women should abstain when planning a pregnancy.

Pregnant Smokers' Intention to Switch From Cigarettes to E-Cigarettes: A Reasoned Action Approach

INTRODUCTION

This study used the reasoned action approach (RAA) to examine 1) factors associated with pregnant smokers' intention to switch from cigarettes to e-cigarettes and 2) the influence that intention to switch had on future expectations to resume cigarette use postpartum.

METHODS

U.S. pregnant women (N = 267) who reported past 30-day use of cigarettes completed an online cross-sectional survey between November and December 2019. A 30-item scale measured RAA constructs (intention, instrumental attitudes, experiential attitudes, injunctive norms, descriptive norms, perceived autonomy, and perceived capacity). A confirmatory factor analysis confirmed and structural equation modeling tested the RAA constructs' association with intention to switch and the relationship between intention to switch and future expectations to resume smoking after pregnancy.

RESULTS

The confirmatory factor analysis confirmed the seven-factor measurement model. Structural equation modeling found instrumental attitudes (β = 0.43; p < .001) and descriptive norms (β = 0.53; p < .001) were associated with intention to switch from cigarettes to e-cigarettes. However, there were differences between the constructs' relationships with intention between those who did and did not use e-cigarettes in the past 30 days. Intention to switch was inversely related with future expectations to resume smoking postpartum (β = -0.13; p < .001).

CONCLUSIONS

This study examined multiple facets of behavioral decision-making that may influence pregnant smokers' intention to switch to e-cigarettes during pregnancy. In this sample, pregnant people who believed switching from cigarettes to e-cigarettes was important and that other smokers commonly switched during pregnancy reported greater intention to switch. Novel theories, such as the RAA, may provide an optimal lens to understand pregnant smokers' behavioral decision-making process as they consider switching from cigarettes to e-cigarettes.

Prevalence and Distribution of Electronic Cigarette Use Before and During Pregnancy Among Women in 38 States of the United States

INTRODUCTION

To examine the prevalence and the changing pattern of e-cigarette use from preconception to pregnancy.

AIMS AND METHODS

This is a cross-sectional study using data from the multi-site Pregnancy Risk Assessment Monitoring System in the United States, 2016-2017. All participating mothers with information on e-cigarette use before and during pregnancy were included. Self-reported information about e-cigarette use were assessed using questionnaires. Weighted prevalences of e-cigarette use before and during pregnancy were calculated. Multivariable logistic regressions were used to examine the association between various demographic characteristics and e-cigarette use before or during pregnancy.

RESULTS

This study included 69 508 pregnant women from 38 states in the United States. The weighted prevalence of e-cigarette use before pregnancy and during the last 3 months of pregnancy was 3.6% (95% confidence interval [CI] 3.4%-3.9%) and 1.1% (0.9%-1.2%), respectively. The prevalence varied across states, ranging from 1.3% to 8.3% for e-cigarette use before pregnancy and from 0.1% to 3.4% for e-cigarette use during the last 3 months of pregnancy. Among women who used e-cigarettes before pregnancy, 24.4% (21.7%-27.1%) continued to use e-cigarettes during pregnancy. Among women who used e-cigarettes during pregnancy, 62.3% (56.5%-68.0%) were dual users. In multivariable analyses, cigarette smoking was most strongly associated with e-cigarette use. The adjusted odds ratio comparing smokers with nonsmokers before pregnancy was 11.10 (95% CI 9.34-13.20) for e-cigarette use before pregnancy and 6.72 (95% CI 4.38-10.31) for e-cigarette use during pregnancy.

CONCLUSIONS

Using data from 38 states in the United States, we showed geographical variations in the prevalence of e-cigarette use before and during pregnancy. Among women who used e-cigarettes before pregnancy, a quarter of them continued to use e-cigarettes during pregnancy. Conventional cigarette use is a strong risk factor for e-cigarette use before and during pregnancy. The prevalence of e-cigarette use needs to be monitored continuously.

IMPLICATIONS

This study provides important information to understand the status and changing patterns of e-cigarette use in pregnant women in the United States. Among pregnant women in 38 states in the United States, 3.6% of them used e-cigarettes during the 3 months before pregnancy and 1.1% used them during the last 3 months of pregnancy. The prevalence varied across states. A quarter of women who used e-cigarettes before pregnancy continued to use e-cigarettes during pregnancy. Cigarette smoking is the strongest predictor of e-cigarette use. Future research about health effects of e-cigarette use during pregnancy is in urgent need.

Longitudinal Examination of Prenatal Tobacco Switching Behaviors and Birth Outcomes, Including Electronic Nicotine Delivery System (ENDS) and Dual Use

INTRODUCTION

In the US, approximately 8% of pregnant women smoke, and 5-11.9% currently use ENDS products. The health effects of ENDS use are debated; however, most contain nicotine which is known to cause adverse perinatal outcomes. Studies have shown adult ENDS users significantly alter use behaviors over time (switch to conventional cigarettes-only or dual use) thus complicating efforts to examine health effects of ENDS use. The purpose of this study was to describe switching behaviors and associated birth outcomes among infants of women using conventional cigarettes only, ENDS-only, or both.

METHODS

This was a multisite, longitudinal study of biologically confirmed perinatal tobacco users, with nicotine product use assessed each trimester. For the purpose of analysis, participants were defined as switchers, no-switchers, or quitters. Birth outcomes were abstracted from electronic medical records. Analysis included descriptive statistics, linear and multivariate logistic regression adjusted for age, preterm birth, smoking behavior in the first trimester, and an interaction between smoking switching behavior and smoking behavior in the first trimester. Analysis was conducted using SAS v9.4 with significance determined as p < 0.05.

RESULTS

At enrollment, 48.6% of participants used only conventional cigarettes, 41.7% were dual users, and 10% used ENDS-only. While almost two-thirds of participants used the same tobacco product throughout pregnancy, 26% reported switching behaviors that were complex and not easily clustered. No differences were found in birth outcomes between switchers and no-switchers; however, a difference emerged in birth weight between no-switchers and quitters.

DISCUSSION

Given the limited data on health effects of ENDS use, and the known harmful consequences of perinatal nicotine use, capturing and classifying product switching behaviors is imperative to inform public health, and remains a challenge requiring further research.

Understanding Rising Electronic Cigarette Use

Vaping is the act of inhaling an aerosol generated by an electronic cigarette (e-cigarette), a battery-powered device that heats a reservoir of liquid, typically nicotine-containing, to deliver contents to the user. E-cigarettes were initially introduced as a means of smoking cessation, although evidence of their effectiveness is limited. There is a widespread perception that these products are a safer alternative to conventional cigarettes, driven in large part by marketing efforts by e-cigarette manufacturers. Yet to achieve vaporization, temperatures are so high that components of the device hardware, such as metals, plastics, rubber and foam, are aerosolized and inhaled along with the vaporized e-liquid containing nicotine, flavoring and solvents. We do not fully understand the health consequences of such aerosol exposure, particularly long-term effects, but short-term negative cardiovascular and respiratory effects have been demonstrated. Very few studies have evaluated the reproductive effect of e-cigarette use. We do not know whether vaping during pregnancy affects birth outcomes or the lifelong health of the fetus. There has been an exponential rise in the use of e-cigarettes in the United States since their introduction, particularly among youths, while concurrently there has been a laudable reduction in conventional cigarette use. It is imperative that obstetrician-gynecologists have a basic understanding of e-cigarettes, screen all patients as is consistently done for conventional smoking, and provide resources to patients about potential negative consequences of use.

Adverse Birth Outcomes Associated With Prepregnancy and Prenatal Electronic Cigarette Use

OBJECTIVE

To evaluate the risk of adverse birth outcomes among adults who use electronic cigarettes (e-cigarettes) before and during pregnancy.

METHODS

Data from the 2016-2018 PRAMS (Pregnancy Risk Assessment Monitoring System) were used to assess the association between e-cigarette use during the 3 months before and last 3 months of pregnancy among 79,176 individuals with a recent live birth and the following birth outcomes: preterm birth, small for gestational age, and low birth weight (LBW). Adjusted prevalence ratios were generated using average marginal predictions from multivariable logistic regression models. Models were stratified by prenatal combustible cigarette smoking and frequency of e-cigarette use (daily or less than daily use).

RESULTS

In the 3 months before pregnancy, 2.7% (95% CI 2.6-2.9%) of respondents used e-cigarettes; 1.1% (95% CI 1.0-1.2%) used e-cigarettes during the last 3 months of pregnancy. Electronic cigarette use before pregnancy was not associated with adverse birth outcomes. Electronic cigarette use during pregnancy was associated with increased prevalence of LBW compared with nonuse (8.1% vs 6.1%; adjusted prevalence ratio 1.33; 95% CI 1.06-1.66). Among respondents who did not also smoke combustible cigarettes during pregnancy (n=72,256), e-cigarette use was associated with higher prevalence of LBW (10.6%; adjusted prevalence ratio 1.88; 95% CI 1.38-2.57) and preterm birth (12.4%; adjusted prevalence ratio 1.69; 95% CI 1.20-2.39). When further stratified by frequency of e-cigarette use, associations were seen only for daily users.

CONCLUSION

E-cigarette use during pregnancy, particularly when used daily by individuals who do not also smoke combustible cigarettes, is associated with adverse birth outcomes.

Patterns of combustible and electronic cigarette use during pregnancy and associated pregnancy outcomes

Although pregnant smokers may perceive electronic cigarettes (e-cigarettes) as safe alternatives to smoking combustible cigarettes, few studies have evaluated perinatal e-cigarette use and its associated health effects. We analyzed data from the Pregnancy Risk Assessment Monitoring System (PRAMS, 2016-2018) for 16,022 women who recently gave birth and reported smoking combustible cigarettes prior to pregnancy. Using average marginal predictive values from multivariable logistic regression to produce adjusted prevalence ratios (aPRs), we estimated the prevalence of combustible cigarette smoking during pregnancy and adverse birth outcomes associated with e-cigarette use. In total, 14.8% of smoking women reported using e-cigarettes prior to pregnancy. There was no association between e-cigarette use prior to pregnancy and combustible cigarette smoking during pregnancy (aPR 0.95; 95% CI 0.88, 1.02); however, e-cigarette use during pregnancy was associated with higher prevalence of combustible cigarette smoking during pregnancy (aPR 1.65; 95% CI 1.52, 1.80). In this sample, we did not observe evidence to support reduced risk of preterm birth, small-for-gestational age and low birthweight compared to combustible cigarette smoking during pregnancy. The prevalence of LBW was higher for those who used e-cigarettes, even exclusively, compared to women who quit smoking cigarettes entirely. These results suggest that e-cigarettes should not be considered a safe alternative to combustible cigarette smoking during pregnancy.

Long-term cerebrovascular dysfunction in the offspring from maternal electronic cigarette use during pregnancy

Electronic cigarettes (E-cigs) have been promoted as harm-free or less risky than smoking, even for women during pregnancy. These claims are made largely on E-cig aerosol having fewer number of toxic chemicals compared with cigarette smoke. Given that even low levels of smoking are found to produce adverse birth outcomes, we sought to test the hypothesis that vaping during pregnancy (with or without nicotine) would not be harm-free and would result in vascular dysfunction that would be evident in offspring during adolescent and/or adult life. Pregnant female Sprague Dawley rats were exposed to E-cig aerosol (1 h/day, 5 days/wk, starting on gestational day 2 until pups were weaned) using e-liquid with 0 mg/mL (E-cig0) or 18 mg/mL nicotine (E-cig18) and compared with ambient air-exposed controls. Body mass at birth and at weaning were not different between groups. Assessment of middle cerebral artery (MCA) reactivity revealed a 51%-56% reduction in endothelial-dependent dilation response to acetylcholine (ACh) for both E-cig0 and E-cig18 in 1-mo, 3-mo (adolescent), and 7-mo-old (adult) offspring (P < 0.05 compared with air, all time points). MCA responses to sodium nitroprusside (SNP) and myogenic tone were not different across groups, suggesting that endothelial-independent responses were not altered. The MCA vasoconstrictor response (5-hydroxytryptamine, 5-HT) was also not different across treatment and age groups. These data demonstrate that maternal vaping during pregnancy is not harm-free and confers significant cerebrovascular health risk/dysfunction to offspring that persists into adult life. NEW & NOTEWORTHY These data established that vaping electronic cigarettes during pregnancy, with or without nicotine, is not safe and confers significant risk potential to the cerebrovascular health of offspring in early and adult life. A key finding is that vaping without nicotine does not protect offspring from cerebrovascular dysfunction and results in the same level of cerebrovascular dysfunction (compared with maternal vaping with nicotine), indicating that the physical and/or chemical properties from the base solution (other than nicotine) are responsible for the cerebrovascular dysfunction that we observed. Listen to this article's corresponding podcast at https://ajpheart.podbean.com/e/maternal-vaping-impairs-vascular-function-in-theoffspring/.

The Intergenerational Transmission of Developmental Nicotine Exposure-Induced Neurodevelopmental Disorder-Like Phenotypes is Modulated by the Chrna5 D397N Polymorphism in Adolescent Mice

Maternal tobacco smoking during pregnancy constitutes developmental nicotine exposure (DNE) and is associated with nicotine dependence and neurodevelopmental disorders in both children and grandchildren as well as animal models thereof. Genetic variants such as the CHRNA5 single nucleotide polymorphism (SNP) rs16969968, which leads to an aspartic acid to asparagine substitution at amino acid position 398 (D398N) in the alpha-5 nicotinic acetylcholine receptor subunit, can also confer risk for nicotine dependence and neurodevelopmental disorders in the absence of DNE. However, the degrees to which, the consequences of maternal smoking on offspring outcomes are influenced by genetic variants and interactions therewith are not well understood. Addressing this void in the literature, the present study utilizes a DNE mouse model engineered to possess the equivalent of the human D398N SNP in CHRNA5 (D397N SNP in mice) to assess how the N397 risk allele impacts the induction and intergenerational transmission of a range of neurodevelopmental disorder-related behavioral phenotypes in first- and second-generation DNE offspring. Results reveal that offspring possessing the N397 variant in the absence of DNE as well as DNE offspring and grand offspring possessing theD397 variant exhibit analogous neurodevelopmental disorder-like phenotypes including hyperactivity, risk-taking behaviors, aberrant rhythmicity of activity, and enhanced nicotine consumption. DNE amplified these behavioral anomalies in first-generation N397 progeny, but the severity of DNE-evoked behavioral perturbations did not significantly differ between first-generation D397 and N397 DNE mice for any measure. Remarkably, the behavioral profiles of second-generation N397 DNE progeny closely resembled DNE-naive D397 mice, suggesting that the N397 variant may protect against the intergenerational transmission of DNE-induced neurodevelopmental disorder-like behaviors.

Associations between electronic nicotine delivery systems and birth outcomes

OBJECTIVES

Nicotine crosses the placenta and is a known teratogen. The use of electronic nicotine delivery systems (ENDS) has increased among pregnant women in the US, but there is limited knowledge about their effects on birth outcomes. We examined the associations between ENDS and cigarette use during pregnancy with birth outcomes.

METHODS

We conducted a cross-sectional analysis of 57,046 respondents from 32 US states in the 2016-2017 Pregnancy Risk Assessment Monitoring System. Respondents self-reported use of ENDS and cigarettes during the last 3 months of pregnancy; this was linked with birth outcomes documented on the birth certificate, including birth weight, gestational age, small-for-gestational age, and preterm birth.

RESULTS

During the last 3 months of pregnancy, 0.5% of women used ENDS only, 0.8% were dual users of ENDS and cigarettes, and 8.0% used cigarettes only. In adjusted models, infants of women who used ENDS only weighed 57.8 grams less (95% CI -134.2, 18.6; p = .14) and were born 0.21 weeks earlier (95% CI -0.45, 0.03; p = .09) than infants of non-users. Infants born to dual users were 193.9 grams less (95% CI -274.9, -112.8; p < .01) and had a 1.93 higher odds of being born small-for-gestational age (95% CI 1.31, 2.83; p < .01) than infants of non-users.

CONCLUSIONS

Our results provide some indication that prenatal ENDS use may adversely affect birth outcomes by reducing birth weight and gestational age. Estimates were imprecise, suggesting that larger samples of ENDS users with more detailed information about patterns of use are needed.

Active and Passive Exposure to Tobacco and e-Cigarettes During Pregnancy

OBJECTIVES

Active and passive exposure to tobacco cigarettes during pregnancy is associated with multiple negative health outcomes for the fetus. In addition, exposure to e-cigarettes has been progressively discussed as a new threat to fetal health. Until now, there has been a lack of studies examining active and passive exposure to tobacco and e-cigarettes among pregnant women. The objective of our current STudy on E-cigarettes and Pregnancy (STEP) was to advance and complement the current knowledge regarding active and passive exposure to tobacco and e-cigarettes before pregnancy and during early and late pregnancy.

METHODS

One element of the STEP study was a quantitative cross-sectional design: A sample of 540 pregnant women recruited at an obstetrician clinic in Hamburg from April 2018 to January 2019 were surveyed once via a standardized questionnaire and provided complete information regarding their consumption of tobacco and e-cigarettes. We performed a descriptive analysis of tobacco and e-cigarette use before pregnancy and during early and late pregnancy, as well as bivariate analysis of these variables with sociodemographic determinants. Passive exposure was assessed by asking the participating pregnant women about the consumption of tobacco and e-cigarettes by their partners, in general, and in their homes.

RESULTS

Before pregnancy, 20.0% of the participants used tobacco cigarettes exclusively, 1.3% used e-cigarettes exclusively, and 6.5% were dual users. Educational level was significantly associated with tobacco cigarette use (p < 0.001) and dual use (p = 0.047) before pregnancy. During early (late) pregnancy, 8.7% (2.8%) used tobacco cigarettes and 0.4% (0.0%) used e-cigarettes exclusively. Twenty-point nine percent of women's partners consumed tobacco cigarettes exclusively, 2.7% consumed e-cigarettes exclusively, and 2.7% consumed both. A total of 8.5% (16.7%) of the partners who consumed tobacco cigarettes exclusively (e-cigarettes exclusively) did so in the women's homes.

CONCLUSIONS FOR PRACTICE

Among pregnant women, the use of tobacco cigarettes remains prominent before and during pregnancy, while e-cigarette use predominately occurs before pregnancy. Our study shows that pregnant women are frequently exposed to their partners' tobacco and e-cigarette use within their homes. Strategies to reduce such exposure should be further intensified.

Stressful life events and electronic cigarette use during pregnancy

RATIONALE

Smoking during pregnancy poses a significant health risk for infant well-being. Prior research has linked experiencing stressful life events (SLEs) during pregnancy to prenatal smoking. However, extant research has not assessed whether SLEs experienced during pregnancy are a risk factor for prenatal electronic cigarette use.

OBJECTIVE

This study investigates the association between SLEs and electronic cigarette use during the third trimester of pregnancy.

METHODS

We employ data on 70,626 recent mothers from the 2016-2018 Pregnancy Risk Assessment Monitoring System. Logistic and multinomial logistic regression models were used to examine the association between SLEs and electronic cigarette use during the third-trimester of pregnancy.

RESULTS

The prevalence of electronic cigarette use increased alongside an accumulating history of SLEs (0 SLEs = 0.4%; 1-2 SLEs = 0.9%; 3-5 SLEs = 1.9%; 6+ SLEs = 5.0%). Logistic regression models found 6 or more SLEs were associated with 4.7 times higher odds of electronic cigarette use relative to 0 SLEs after adjusting for demographic and socioeconomic characteristics (AOR = 4.705, 95% CI = 2.960, 7.479). Study findings also showed that women who experienced greater levels of SLEs had a higher prevalence of using any nicotine products (i.e., exclusive electronic cigarette user, exclusive cigarette user, dual user), relative to being a non-smoker. Findings from multinomial logistic regression models revealed that a higher number of SLEs was associated with an increased relative risk of all smoking outcomes. Still, these associations were particularly pronounced in the case of exclusive electronic cigarette user (ARR = 8.485, 95% CI = 4.900, 14.692) and dual-use (ARR = 8.348, 95% CI = 4.113, 16.945) when participants experienced 6 or more SLEs (relative to 0 SLEs).

CONCLUSIONS

Considering the potentially harmful ramifications of electronic cigarette use during pregnancy there is a need for interventions that reduce stressful experiences and decrease smoking during pregnancy.

Study on E-Cigarettes and Pregnancy (STEP) - Results of a Mixed Methods Study on Risk Perception of E-Cigarette Use During Pregnancy

Introduction E-cigarette use during pregnancy is a risk factor for maternal and fetal health. Early studies on animals showed that in utero exposure to e-cigarettes can have negative health outcomes for the fetus. There has been only limited research into the risk perceptions of e-cigarette use during pregnancy. This study was conducted to comprehensively characterize the constructs of risk perceptions with regard to e-cigarette use during pregnancy using an I ntegrated H ealth B elief M odel (IHBM).

Methods Our ST udy on E -cigarettes and P regnancy (STEP) used a mixed methods approach, with the study divided into an initial qualitative part and a quantitative part. A netnographic approach was used for the first part, which consisted of the analysis of 1552 posts from 25 German-language online discussion threads on e-cigarette use during pregnancy. Using these qualitative results, a quantitative questionnaire was developed to explore risk perception constructs about e-cigarette use during pregnancy. This questionnaire was subsequently administered to pregnant women (n = 575) in one hospital in Hamburg, Germany. Descriptive and bivariate analysis was used to examine differences in risk perception according to participantsʼ tobacco and e-cigarette user status before and during pregnancy. While the study design, methods and sample have been extensively described in our recently published study protocol in the January 2020 issue of Geburtshilfe und Frauenheilkunde , this paper is devoted to a presentation of the results of our mixed methods study.

Results Themes related to perceived threats identified in the qualitative study part were nicotine-related health risks and potential health risks of additional ingredients . Perceived benefits were possibility and facilitation of smoking cessation and a presumed potential to reduce harm . The subsequent quantitative part showed that nearly all participants (99.3%) perceived e-cigarettes which contained nicotine as constituting a threat to the health of the unborn child. The most commonly perceived barrier was health-related (96.6%), while the most commonly perceived benefit was a reduction in the amount of tobacco cigarettes consumed (31.8%). We found that particularly perceived benefits varied depending on the participantʼs tobacco and e-cigarette user status.

Conclusion When considering future prevention strategies, the potential health risks and disputed effectiveness of e-cigarettes as a tool for smoking cessation need to be taken into account and critically discussed.

Incarceration exposure and electronic cigarette use during pregnancy: Findings from the pregnancy risk assessment monitoring system, 2016-2018

Smoking during pregnancy is a serious public health concern that poses risks for maternal and infant health. Considering the rise of electronic cigarette use in recent years, there is also growing concern about electronic cigarette use during pregnancy. Recent research has begun to explore correlates of electronic cigarette use among pregnant women. While research has revealed a strong connection between incarceration and smoking, scholars have yet to examine the connection between a woman's exposure to incarceration in the year prior to birth - either personally or vicariously through her husband or partner - and prenatal electronic cigarette use. The current study uses data from 74,554 recent mothers from the 2016-2018 Pregnancy Risk Assessment Monitoring System. Logistic regression and multinomial logistic regression models were used to assess the association between incarceration exposure and electronic cigarette use. The findings indicate a robust association between incarceration exposure and electronic cigarette use during pregnancy. Specifically, analyses demonstrate that incarceration-exposed women were approximately 2.7 times (AOR = 2.699, 95% CI = 1.939, 3.755) as likely to use electronic cigarettes after adjusting for a host of demographic, economic, health, and pregnancy related characteristics. Additional analyses reveal this association remains after accounting for conventional cigarette use during pregnancy. Considering the potential harmful health ramifications for electronic cigarette use during pregnancy, these findings suggest a need for interventions targeting electronic cigarette use among incarceration-exposed populations and point to electronic cigarette use among pregnant women in particular as an important area of focus for both criminal justice and public health practitioners.

Prenatal Exposure to Electronic-Cigarette Aerosols Leads to Sex-Dependent Pulmonary Extracellular-Matrix Remodeling and Myogenesis in Offspring Mice

Electronic-cigarette (e-cig) vaping is a serious concern, as many pregnant women who vape consider it safe. However, little is known about the harmful effects of prenatal e-cig exposure on adult offspring, especially on extracellular-matrix (ECM) deposition and myogenesis in the lungs of offspring. We evaluated the biochemical and molecular implications of maternal exposure during pregnancy to e-cig aerosols on the adult offspring of both sexes, with a particular focus on pulmonary ECM remodeling and myogenesis. Pregnant CD-1 mice were exposed to e-cig aerosols with or without nicotine, throughout gestation, and lungs were collected from adult male and female offspring. Compared with the air-exposed control group, female mice exposed to e-cig aerosols, with or without nicotine, demonstrated increased lung protein abundance of LEF-1 (lymphoid enhancer-binding factor 1), fibronectin, and E-cadherin, whereas altered E-cadherin and PPARγ (peroxisome proliferator-activated receptor γ) levels were observed only in males exposed to e-cig aerosols with nicotine. Moreover, lipogenic and myogenic mRNAs were dysregulated in adult offspring in a sex-dependent manner. PAI-1 (plasminogen activator inhibitor-1), one of the ECM regulators, was significantly increased in females exposed prenatally to e-cig aerosols with nicotine and in males exposed to e-cig aerosols compared with control animals exposed to air. MMP9 (matrix metalloproteinase 9), a downstream target of PAI-1, was downregulated in both sexes exposed to e-cig aerosols with nicotine. No differences in lung histology were observed among any of the treatment groups. Overall, adult mice exposed prenatally to e-cig aerosols could be predisposed to developing pulmonary disease later in life. Thus, these findings suggest that vaping during pregnancy is unsafe and increases the propensity for later-life interstitial lung diseases.

Effects of E-Cigarette Exposure on Prenatal Life and Childhood Respiratory Health: A Review of Current Evidence

In the last decade, widespread use of E-cigarettes (EC) has occurred all over the world. Whereas, a large amount of evidence on harm to children from conventional cigarette exposure is available, data on health effects in this population throughout different vulnerability windows are still a matter of concern. Exposure to EC during pregnancy may compromise placental function, resulting in fetal structural abnormalities. Specifically, this may cause physio-pathologic changes in the developing lung, which in turn may impair respiratory health later in life. Furthermore, there is evidence that using EC can cause both short- and long-term respiratory problems in the pediatric population and there is great concern for future young people with nicotine addiction. The low parental perception of the risks connected to EC exposure for children increases their susceptibility to harmful effects from passive vaping. This minireview aims to summarize the current evidence focusing on: (i) prenatal effects of EC passive exposure; (ii) post-natal respiratory effects of EC exposure in youth; (iii) parental attitudes toward EC use and perception of children's health risks connected to EC exposure; and (iv) addressing gaps in our current evidence.

Gestational Women's Perceptions About the Harms of Cigarette and E-Cigarette Use During Pregnancy

OBJECTIVES

The purpose of this study was to examine differences between perceived harm of cigarette and electronic cigarette (e-cigarette) use while pregnant and differences between healthcare providers' communication about these products during pregnancy.

METHODS

A convenience sample of gestational women (n = 218; ages 18-45) living in the US completed an online survey between May and December 2017. Participants reported perceived likelihood of adverse health outcomes (e.g., low birth weight, sudden infant death syndrome) among infants/children born to mothers who used cigarettes/e-cigarettes. T-tests and two-way ANOVAs examined differences between risk perceptions of using cigarettes/e-cigarettes while pregnant based on pregnancy status (previously pregnant, currently pregnant, future pregnant). Chi-square analyses examined differences between healthcare provider communication about cigarette/e-cigarette use during pregnancy.

RESULTS

Overall, participants believed adverse health outcomes were significantly more likely to be caused by maternal use of cigarettes than e-cigarettes. Participants who planned to be pregnant reported higher endorsement that smoking combustible cigarettes would cause a miscarriage (p < .05) or increased blood pressure (p < .05) for a child than currently pregnant participants. Participants reported healthcare providers asked about (p < .05), advised them not to use (p < .001), and talked to them about health effects of smoking combustible cigarettes while pregnant (p < .001) significantly more than e-cigarettes.

CONCLUSIONS FOR PRACTICE

Healthcare providers working with pregnant women should perform the 5As behavioral intervention method to provide pregnant women with tobacco cessation care. They should also discuss the absolute harm nicotine exposure (via cigarettes or e-cigarettes) can have on fetal health and development.

Vaping During Pregnancy: What Are the Potential Health Outcomes and Perceptions Pregnant Women Have?

The prevalence of electronic nicotine delivery systems, such as vaping, is a growing public health concern, and there is limited information on the use of these devices during pregnancy. The objective of this rapid review was to summarize the available literature on human studies of the potential maternal or fetal health effects of vaping or women's perceptions of vaping during pregnancy. A systematic search was completed in the following databases: Medline, EMBASE, Scopus, Web of Science, and CINAHL. A search strategy was developed combining the terms pregnancy and vaping. Findings were divided into two groups and summarized as: 1) Health outcomes following vaping during pregnancy; and 2) Perceptions pregnant women have related to vaping during pregnancy. A total of 760 articles were retrieved and, after applying the inclusion/exclusion criteria and screening, 19 studies were included. Five included studies provided evidence on potential health outcomes and 14 were focused on perceptions. There is emerging evidence that vaping during pregnancy may increase the risk of small for gestational age newborns. Pregnant women generally report that they used vaping products during pregnancy for smoking cessation and perceived that this was a healthier alternative to traditional cigarettes. Overall, there was consensus that there is a lack of information on maternal and fetal health outcomes following vaping during pregnancy. Based on the findings of this rapid review, there is an urgent need for high-quality studies in pregnant women to evaluate the potential in utero and long-term effects of exposure to prenatal vaping.

Electronic cigarettes: A position statement from the Thoracic Society of Australia and New Zealand

The TSANZ develops position statements where insufficient data exist to write formal clinical guidelines. In 2018, the TSANZ addressed the question of potential benefits and health impacts of electronic cigarettes (EC). The working party included groups focused on health impacts, smoking cessation, youth issues and priority populations. The 2018 report on the Public Health Consequences of E-Cigarettes from the United States NASEM was accepted as reflective of evidence to mid-2017. A search for papers subsequently published in peer-reviewed journals was conducted in August 2018. A small number of robust and important papers published until March 2019 were also identified and included. Groups identified studies that extended, modified or contradicted the NASEM report. A total of 3793 papers were identified and reviewed, with summaries and draft position statements developed and presented to TSANZ membership in April 2019. After feedback from members and external reviewers, a collection of position statements was finalized in December 2019. EC have adverse lung effects and harmful effects of long-term use are unknown. EC are unsuitable consumer products for recreational use, part-substitution for smoking or long-term exclusive use by former smokers. Smokers who require support to quit smoking should be directed towards approved medication in conjunction with behavioural support as having the strongest evidence for efficacy and safety. No specific EC product can be recommended as effective and safe for smoking cessation. Smoking cessation claims in relation to EC should be assessed by established regulators.

Tobacco and Nicotine Cessation During Pregnancy: ACOG Committee Opinion, Number 807

Pregnant women should be advised of the significant perinatal risks associated with tobacco use, including orofacial clefts, fetal growth restriction, placenta previa, abruptio placentae, preterm prelabor rupture of membranes, low birth weight, increased perinatal mortality, ectopic pregnancy, and decreased maternal thyroid function. Children born to women who smoke during pregnancy are at an increased risk of respiratory infections, asthma, infantile colic, bone fractures, and childhood obesity. Pregnancy influences many women to stop smoking, and approximately 54% of women who smoke before pregnancy quit smoking directly before or during pregnancy. Smoking cessation at any point in gestation benefits the pregnant woman and her fetus. The greatest benefit is observed with cessation before 15 weeks of gestation. Although cigarettes are the most commonly used tobacco product in pregnancy, alternative forms of tobacco use, such as e-cigarettes or vaping products, hookahs, and cigars, are increasingly common. Clinicians should advise cessation of tobacco products used in any form and provide motivational feedback. Although counseling and pregnancy-specific materials are effective cessation aids for many pregnant women, some women continue to use tobacco products. Clinicians should individualize care by offering psychosocial, behavioral, and pharmacotherapy interventions. Available cessation-aid services and resources, including digital resources, should be discussed and documented regularly at prenatal and postpartum follow-up visits.

Replacing smoking with vaping during pregnancy: Impacts on metabolic health in mice

Smoking is a significant risk factor for the development of metabolic diseases. Due to social pressures to quit smoking, many pregnant women are vaping as an alternative nicotine source. However, the metabolic consequences of replacing tobacco cigarettes with e-cigarettes during pregnancy are unknown. Therefore, in the mothers and their offspring, we investigated the metabolic and hepatic impacts of replacing cigarette smoke with e-vapour during pregnancy. Female BALB/c mice were either air-exposed or cigarette smoke-exposed (SE) from six weeks before pregnancy until lactation. At mating, a subset of the SE mice were instead exposed to e-vapour. Markers of glucose and lipid metabolism were measured in the livers and plasma, from the mothers and their male offspring (13 weeks). In the SE mothers, plasma insulin levels were reduced, leading to downstream increases in hepatic gluconeogenesis and plasma non-esterified fatty acids (NEFA). In the e-vapour replacement mothers, these changes were not as significant. In the SE offspring, there was impaired glucose tolerance, and increased plasma NEFA and liver triglyceride concentrations. E-vapour replacement restored lipid homeostasis but did not improve glucose tolerance. Therefore, in a murine model, low dose e-cigarette replacement during pregnancy is less toxic than cigarette smoke.

E-Cigarette Use Patterns and High-Risk Behaviors in Pregnancy: Behavioral Risk Factor Surveillance System, 2016-2018

INTRODUCTION

The prevalence of e-cigarette use has increased dramatically in the last decade in the U.S. Understanding the prevalence, patterns of use, and risk factor associations of e-cigarette use in pregnant women is particularly important, as this could have potential health implications for the mother and the developing child.

METHODS

Using Behavioral Risk Factor Surveillance System Survey data from 2016 to 2018, adult women of reproductive age (18-49 years) who reported being pregnant (n=7,434) were studied. Self-reported current e-cigarette use was the main exposure. Other measures included combustible cigarette smoking status and high-risk behaviors (including other tobacco, marijuana, or heavy alcohol use; binge drinking; and others). All analyses were done in 2019.

RESULTS

Approximately 2.2% of pregnant women reported current e-cigarette use, of whom 0.6% reported daily use. The highest prevalence of e-cigarette use was observed in the youngest age group of pregnant women (3.2%), with 41.7% of all pregnant current e-cigarette users being aged 18-24 years. There was a marked increase in the prevalence of current use of e-cigarettes among pregnant women from 1.9% in 2016 to 3.8% in 2018. Approximately 46% of pregnant current e-cigarette users reported concomitant cigarette smoking. Compared with pregnant never e-cigarette users, pregnant current e-cigarette users had a higher prevalence of other tobacco product use, marijuana use, heavy alcohol intake, binge drinking, and other high-risk behaviors.

CONCLUSIONS

These findings underscore the need to strengthen prevention and policy efforts, specifically in the vulnerable subgroup of pregnant women.

Electronic Cigarette Use During Preconception and/or Pregnancy: Prevalence, Characteristics, and Concurrent Mental Health Conditions

Background: Electronic cigarettes (e-cigarettes) are increasing in popularity in the United States. Prior prevalence estimates of e-cigarette use in pregnancy range from 1% to 15%. Materials and Methods: We assessed prevalence of e-cigarette and conventional cigarette use during preconception or pregnancy in a large sample of racially/ethnically diverse, low-income pregnant women via telephone survey (2015-2018) and compared sociodemographic characteristics and mental health conditions. Results: Of 1365 pregnant women surveyed, 54 (4.0%) reported e-cigarette use (regardless of other tobacco use), 372 (27.3%) reported conventional cigarette use without e-cigarette use (conventional cigarette use), and 939 (68.8%) reported no tobacco or nicotine replacement therapy (NRT) product use during the preconception period and/or pregnancy. Seventy-four percent of women using e-cigarettes reported also using conventional cigarettes. Women who used e-cigarettes were more likely to report high school education or greater, income <$30,000, White race, and non-Hispanic ethnicity than women who used conventional cigarettes. Women who used e-cigarettes were more likely than women who used conventional cigarettes or no tobacco/NRT to report symptoms of depression. Women who used e-cigarettes and women who used conventional cigarettes were more likely than women who used no tobacco/NRT to report a history of severe mental health conditions, alcohol use during pregnancy, and marijuana or other drug use during preconception. Conclusions: In this sample, 4% of women used e-cigarettes during preconception and/or pregnancy and most also used conventional cigarettes. Increased efforts by providers to screen for tobacco (including use of e-cigarette) and polysubstance use and to provide cessation services could improve outcomes of mothers and children.

Factors influencing the uptake and use of nicotine replacement therapy and e-cigarettes in pregnant women who smoke: a qualitative evidence synthesis

BACKGROUND

Nicotine replacement therapy (NRT) delivers nicotine without the toxic chemicals present in tobacco smoke. It is an effective smoking cessation aid in non-pregnant smokers, but there is less evidence of effectiveness in pregnancy. Systematic review evidence suggests that pregnant women do not adhere to NRT as prescribed, which might undermine effectiveness. Electronic cigarettes (e-cigarettes) have grown in popularity, but effectiveness and safety in pregnancy are not yet established. The determinants of uptake and use of NRT and e-cigarettes in pregnancy are unknown.

OBJECTIVES

To explore factors affecting uptake and use of NRT and e-cigarettes in pregnancy.

SEARCH METHODS

We searched MEDLINE(R), CINAHL and PsycINFO on 1 February 2019. We manually searched OpenGrey database and screened references of included studies and relevant reviews. We also conducted forward citation searches of included studies.

SELECTION CRITERIA

We selected studies that used qualitative methods of data collection and analysis, included women who had smoked in pregnancy, and elicited participants' views about using NRT/e-cigarettes for smoking cessation or harm reduction (i.e. to smoke fewer cigarettes) during pregnancy.

DATA COLLECTION AND ANALYSIS

We identified determinants of uptake and use of NRT/e-cigarettes in pregnancy using a thematic synthesis approach. Two review authors assessed the quality of included studies with the Wallace tool. Two review authors used the CERQual approach to assess confidence in review findings. The contexts of studies from this review and the relevant Cochrane effectiveness review were not similar enough to fully integrate findings; however, we created a matrix to juxtapose findings from this review with the descriptions of behavioural support from trials in the effectiveness review.

MAIN RESULTS

We included 21 studies: 15 focused on NRT, 3 on e-cigarettes, and 3 on both. Studies took place in five high-income countries. Most studies contributed few relevant data; substantially fewer data were available on determinants of e-cigarettes. Many studies focused predominantly on issues relating to smoking cessation, and determinants of NRT/e-cigarette use was often presented as one of the themes. We identified six descriptive themes and 18 findings within those themes; from these we developed three overarching analytical themes representing key determinants of uptake and adherence to NRT and/or e-cigarettes in pregnancy. The analytical themes show that women's desire to protect their unborn babies from harm is one of the main reasons they use these products. Furthermore, women consider advice from health professionals when deciding whether to use NRT or e-cigarettes; when health professionals tell women that NRT or e-cigarettes are safer than smoking and that it is okay for them to use these in pregnancy, women report feeling more confident about using them. Conversely, women who are told that NRT or e-cigarettes are as dangerous or more dangerous than smoking and that they should not use them during pregnancy feel less confident about using them. Women's past experiences with NRT can also affect their willingness to use NRT in pregnancy; women who feel that NRT had worked for them (or someone they know) in the past were more confident about using it again. However, women who had negative experiences were more reluctant to use NRT. No trials on e-cigarette use in pregnancy were included in the Cochrane effectiveness review, so we considered only NRT findings when integrating results from this review and the effectiveness review. No qualitative studies were conducted alongside trials, making full integration of the findings challenging. Women enrolled in trials would have agreed to being allocated to NRT or control group and would have received standardised information on NRT at the start of the trial. Overall, the findings of this synthesis are less relevant to women's decisions about starting NRT in trials and more likely to help explain trial participants' adherence to NRT after starting it. We considered most findings to be of moderate certainty; we assessed findings on NRT use as being of higher certainty than those on e-cigarette use. This was mainly due to the limited data from fewer studies (only in the UK and USA) that contributed to e-cigarette findings. Overall, we judged studies to be of acceptable quality with only minor methodological issues.

AUTHORS' CONCLUSIONS

Consistent messages from health professionals, based on high-quality evidence and clearly explaining the safety of NRT and e-cigarettes compared to smoking in pregnancy, could help women use NRT and e-cigarettes more consistently/as recommended. This may improve their attitudes towards NRT or e-cigarettes, increase their willingness to use these in their attempt to quit, and subsequently encourage them to stay smoke-free.

Perceptions, Characteristics, and Behaviors of Cigarette and Electronic Cigarette Use among Pregnant Smokers

INTRODUCTION

Smoking during pregnancy is a primary risk factor for adverse perinatal outcomes. Although electronic cigarette (e-cigarette) use has increased, reasons for and behaviors of use are not fully understood. The purpose of this study, composed exclusively of pregnant current smokers, was to describe perceptions of health risks associated with e-cigarette use among pregnant women, describe the use patterns of pregnant dual users (defined as those who simultaneously use conventional/combustible cigarettes and e-cigarettes), and examine smoking-related behaviors between conventional-only (defined as those smoking combustible cigarettes but not e-cigarettes) and dual users.

METHODS

Cross-sectional data from a larger study of pregnant conventional-only and dual users were analyzed. A brief survey measured perceptions of prenatal e-cigarette use and smoking behaviors. Analysis included descriptive statistics, bivariate analysis, and logistic and linear regression analysis.

RESULTS

Among 176 pregnant smokers (38% dual users), more than one-half of participants believed e-cigarettes were harmful to women (56%) and posed harm to the fetus (53%). Among dual users, 41% used their e-cigarette daily, on average eight times per day. Eleven percent of dual users smoked a pack of cigarettes per day, compared with 5% of conventional-only smokers, and dual users scored significantly higher (p = .026) on the Penn State Cigarette Dependence Index. The most common e-cigarette liquid flavor was fruit (64%), and the most frequently reported e-cigarette nicotine concentration was 1-6 mg.

CONCLUSIONS

Characterizing perceptions and behaviors of e-cigarette use during pregnancy is foundational for future research to explore the association between product use and maternal and infant outcomes.

Smoking and use of electronic cigarettes (vaping) in relation to preterm birth and small-for-gestational-age in a 2016 U.S. national sample

Women who smoke may be motivated to switch to vaping (use electronic cigarettes, e-cigs) around pregnancy in seeking to alleviate known hazards of smoking. E-cigs typically contain nicotine but either eliminates or greatly reduces exposure to the combustion products of tobacco. We studied a U.S.-wide representative sample of 31,973 live singleton births in 2016. In the three months before pregnancy, 5029 (14%) mothers exclusively smoked tobacco ("sole smokers") and 976 (3%) used both tobacco and e-cigs ("dual-users"). Among pre-pregnancy sole smokers, 44% continued to only smoke while 1% became dual-users in late pregnancy. Logistic regression models were used to assess the adjusted odds ratios (aOR) for preterm and small-for-gestational-age (SGA) by reported smoking or vaping in late pregnancy. Compared to women who used neither product ("non-users"), late-pregnancy sole smokers had increased risks for preterm birth (aOR 1.6, 95% CI 1.2-2.0) and SGA (aOR 2.4, 95% CI 1.8-2.9), after adjusting for their pre-pregnancy smoking or vaping status and other confounders. The adjusted models also showed that late-pregnancy sole vapers had similar risk of preterm birth as non-users (aOR 1.2, 95% CI 0.5-2.7). Late-pregnancy dual-users also had similar risk of preterm birth as non-users (aOR 1.3, 95% CI 0.8-2.3). However, late-pregnancy sole vapers and dual-users had increased risk of SGA compared to non-users (aOR 2.4, 95% CI 1.0-5.7 for sole vapers, and aOR 2.3 95% CI 1.3-4.1 for dual-users). These findings suggest that vapers during pregnancy had similar risk of preterm as non-users but still had elevated risk for restricted fetal growth.

Neurotoxicity of e-cigarettes

It appears that electronic cigarettes (EC) are a less harmful alternative to conventional cigarette (CC) smoking, as they generate substantially lower levels of harmful carcinogens and other toxic compounds. Thus, switching from CC to EC may be beneficial for smokers. However, recent accounts of EC- or vaping-associated lung injury (EVALI) has raised concerns regarding their adverse health effects. Additionally, the increasing popularity of EC among vulnerable populations, such as adolescents and pregnant women, calls for further EC safety evaluation. In this state-of-the-art review, we provide an update on recent findings regarding the neurological effects induced by EC exposure. Moreover, we discuss possible neurotoxic effects of nicotine and numerous other chemicals which are inherent both to e-liquids and EC aerosols. We conclude that in recognizing pertinent issues associated with EC usage, both government and scientific researchers must address this public health issue with utmost urgency.

Neuroinflammatory and Behavioral Outcomes Measured in Adult Offspring of Mice Exposed Prenatally to E-Cigarette Aerosols

BACKGROUND

In an effort to decrease the rates of smoking conventional tobacco cigarettes, electronic cigarettes (e-cigarettes) have been proposed as an effective smoking cessation tool. However, little is known about their toxicological impacts. This is concerning given that e-cigarette use is perceived as less harmful than conventional tobacco cigarettes during pregnancy for both the mother and fetus.

OBJECTIVE

The goal of this study was to test the neurodevelopmental consequences of maternal e-cigarette use on adult offspring behavior and neuroimmune outcomes.

METHODS

Pregnant female CD-1 mice were randomly assigned to one of three treatment groups (n=8-10 per group) and exposed daily to either filtered air, propylene glycol and vegetable glycerol (50:50 PG/VG vehicle), or to PG/VG with 16mg/mL nicotine (+Nic). Whole-body exposures were carried out for 3 h/d, 7 d/week, from gestational day (GD)0.5 until GD17.5. Adult male and female offspring (8 weeks old) were assessed across a battery of behavioral assessments followed by region-specific quantification of brain cytokines using multiplex immunoassays.

RESULTS

Adult offspring of both sexes exposed to +Nic exhibited elevated locomotor activity in the elevated plus maze and altered stress-coping strategies in the forced swim task. Moreover, male and female offspring exposed to PG/VG with and without nicotine had a 5.2% lower object discrimination score in the novel object recognition task. In addition to differences in offspring behavior, maternal e-cigarette exposure with nicotine led to a reduction in interleukin (IL)-4 and interferon-gamma (IFNγ) in the diencephalon, as well as lower levels of hippocampal IFNγ (females only). E-cigarette exposure without nicotine resulted in a 2-fold increase of IL-6 in the cerebellum.

DISCUSSION

These findings support previous adverse findings of e-cigarette exposure on neurodevelopment in a mouse model and provide substantial evidence of persistent adverse behavioral and neuroimmunological consequences to adult offspring following maternal e-cigarette exposure during pregnancy. https://doi.org/10.1289/EHP6067.

Developmental nicotine exposure engenders intergenerational downregulation and aberrant posttranslational modification of cardinal epigenetic factors in the frontal cortices, striata, and hippocampi of adolescent mice

BACKGROUND

Maternal smoking of traditional or electronic cigarettes during pregnancy, which constitutes developmental nicotine exposure (DNE), heightens the risk of neurodevelopmental disorders including ADHD, autism, and schizophrenia in children. Modeling the intergenerationally transmissible impacts of smoking during pregnancy, we previously demonstrated that both the first- and second-generation adolescent offspring of nicotine-exposed female mice exhibit enhanced nicotine preference, hyperactivity and risk-taking behaviors, aberrant rhythmicity of home cage activity, nicotinic acetylcholine receptor and dopamine transporter dysfunction, impaired furin-mediated proBDNF proteolysis, hypocorticosteronemia-related glucocorticoid receptor hypoactivity, and global DNA hypomethylation in the frontal cortices and striata. This ensemble of multigenerational DNE-induced behavioral, neuropharmacological, neurotrophic, neuroendocrine, and DNA methylomic anomalies recapitulates the pathosymptomatology of neurodevelopmental disorders such as ADHD, autism, and schizophrenia. Further probing the epigenetic bases of DNE-induced multigenerational phenotypic aberrations, the present study examined the expression and phosphorylation of key epigenetic factors via an array of immunoblot experiments.

RESULTS

Data indicate that DNE confers intergenerational deficits in corticostriatal DNA methyltransferase 3A (DNMT3A) expression accompanied by downregulation of methyl-CpG-binding protein 2 (MeCP2) and histone deacetylase 2 (HDAC2) in the frontal cortices and hippocampi, while the expression of ten-eleven translocase methylcytosine dioxygenase 2 (TET2) is unaltered. Moreover, DNE evokes multigenerational abnormalities in HDAC2 (Ser394) but not MeCP2 (Ser421) phosphorylation in the frontal cortices, striata, and hippocampi.

CONCLUSIONS

In light of the extensive gene regulatory roles of DNMT3A, MeCP2, and HDAC2, the findings of this study that DNE elicits downregulation and aberrant posttranslational modification of these factors in both first- and second-generation DNE mice suggest that epigenetic perturbations may constitute a mechanistic hub for the intergenerational transmission of DNE-induced neurodevelopmental disorder-like phenotypes.