The relatively recent arrival of electronic nicotine delivery systems (ENDS) to the marketplace — and marketing claims that it’s a safer alternative to combustible cigarettes — has led to new questions about risk, particularly in the context of maternal and fetal health.
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“This is a patient population,” says Nikita Desai, MD, pulmonologist and critical care physician in Cleveland Clinic’s Respiratory Institute, “that is typically very motivated to rapidly adopt healthy lifestyle choices.”
Misguided or insufficient data about the safety and/or efficacy of a product like ENDS creates a challenge for clinicians to effectively counsel patients.
Dr. Desai authored a review article on the topic recently published in Obstetric Medicine.
What are ENDS?
The use of ENDS, which have been commercially available in the U.S. since 2007, has steadily increased, despite the declining use of combustible cigarettes. ENDS contain a liquid form of nicotine, in addition to other contents, including propylene glycol, glycerin and flavorings. The device is attached to a heated coil and enables the liquid to be heated, vaporized and inhaled by users.
In 2016, the Food and Drug Administration acquired limited oversight of some of these devices; however, questions remain about the comparative safety of ENDS to combustible cigarettes, long-term health effects and whether there is any validity to the claims that ENDS supports smoking cessation.
ENDS do not produce byproducts like those of a combustible cigarette, such as volatile organic compounds, polycyclic aromatic hydrocarbons and tobacco-specific N-nitrosamines; however, it’s well documented that nicotine exposure poses an independent risk to infant morbidity and mortality.
Emerging ENDS research suggests risk
Preclinical studies have begun to validate the ill effects of ENDS. Findings from one study demonstrated that fetal exposure to ENDS led to the increased production of pro-inflammatory cytokines in the offspring of mouse models.1 In similar preclinical models, researchers found dysregulation in frontal cortex gene expression and a decrease in hippocampal gene expression.2 Reduction in offspring weight and crown-rump length has also demonstrated correlation with ENDS use.3
One in vitro study showed that fetal exposure to vapor from the device resulted in a significant reduction in trophoblast invasion and tube formation, functions that are vital to fetal development.4 Surprisingly, these findings were present in the vapor even in the absence of nicotine. This suggests that even the non-nicotine additives in ENDS incur some level of risk to fetal development.
Common themes in usage
Dr. Desai highlights a few common themes in the literature about how pregnant users perceive the product.
“Even though there is a general acknowledgment that it carries at least some degree of risk, there seems to be a coexisting agreement that it’s a safer alternative to smoking cigarettes,” she says. Users also tend to believe that ENDS is an effective cessation tool, though the literature does not support its safety and efficacy.
“These misconceptions are likely propagated by ENDS marketing strategies and inconsistencies in messaging about the effects of ENDS across the healthcare community,” Dr. Desai says.
As a result, she notes, the majority of pregnant ENDS users are dual users of cigarettes. Many of these patients began ENDS use as a cessation strategy, viewing the product as a safer option, but are at risk for increased nicotine exposure as a dual user.
Reframing the conversation with patients
Further complicating this issue is the discrepancy between reported versus actual rates of nicotine use in pregnancy. The stigma of nicotine use during pregnancy leads to a significant underreporting among patients. Survey data show that ENDS use is between 5% and 7% in pregnant women, although some researchers contend this number is likely as high as 22%.5
While most prenatal caregivers agree that ENDS poses a risk to maternal and fetal health, screening for use remains inconsistent. One survey of obstetric clinicians shows that providers screened for ENDS use about 33% of the time.6 Dr. Desai asserts that until standards of care to screen and counsel pregnant patients on the effects of ENDS are implemented, clinicians should stay current on ENDS-related literature to guide patients responsibly in their practice.
Dr. Desai says the key to initiating an honest dialogue with patients about their smoking habits is to lead with value-free questions about what led them to begin smoking. “It should be a conversation, not a lecture. Do they live or work with someone who smokes? Does it help them manage stress? I can’t make patients quit smoking, but I can help chip away at why they started and help them find healthy coping skills.”
- Chen H, Li G, Chan YL, et al. Maternal e-cigarette exposure in mice alters DNA methylation and lung cytokine expression in offspring. Am J Respir Cell Mol Biol 2018; 58: 366–377.
- Lauterstein DE, Tijerina PB, Corbett K, et al. Frontal cortex transcriptome analysis of mice exposed to electronic cigarettes during early life stages. Int J Environ Res Public Health 2016; 13: 417.
- Orzabal MR, Lunde-Young ER, Ramirez JI, et al. Chronic exposure to e-cig aerosols during early development causes vascular dysfunction and offspring growth deficits. Transl Res 2019; 207: 70–82.
- Raez-Villanueva S, Ma C, Kleiboer S, et al. The effects of electronic cigarette vapor on placental trophoblast cell function. Reprod Toxicol 2018; 81: 115–121.
- Dietz PM, Homa D, England LJ, et al. Estimates of nondisclosure of cigarette smoking among pregnant and nonpregnant women of reproductive age in the United States. Am J Epidemiol 2011; 173: 355–359.
- Northrup TF, Klawans MR, Villarreal YR, et al. Family physicians’ perceived prevalence, safety, and screening for cigarettes, marijuana, and electronic-nicotine delivery systems (ENDS) use during pregnancy. J Am Board Fam Med 2017; 30: 743–757.