REVIEW ARTICLE |
https://doi.org/10.5005/jp-journals-10016-1344 |
Effects of Maternal Electronic Cigarette Smoking vs Tobacco Cigarette Smoking on Fetal Lung Development: A Narrative Review
1,2NITTE Institute of Physiotherapy (NIPT), NITTE (Deemed to be University), Mangaluru, Karnataka, India
Corresponding Author: Aishwarya Nair, NITTE Institute of Physiotherapy (NIPT), NITTE (Deemed to be University), Mangaluru, Karnataka, India, Phone: +91 8879315671, e-mail: aishwaryanair@nitte.edu.in
Received on: 28 September 2023; Accepted: 21 May 2024; Published on: 28 October 2024
ABSTRACT
Background: Smoking during pregnancy is a major risk factor, as it causes abnormal fetal lung growth. Lately, there has been a significant rise in electronic cigarette (e-cigarette) smoking. E-cigarettes have become an alternative method to regular tobacco cigarette smoking. E-cigarettes are devices that deliver nicotine in doses and also contain different flavors, propylene glycol, and vegetable glycerin. Tobacco smoke consists of many compounds, including nicotine. Maternal smoking leads to various gestational problems. The development of the fetal lung undergoes several morphological stages. From that, the fetal lung gets exposed to tobacco smoke and e-cigarette smoke, which can impair lung development, immune response, and cause wheezing.
Methods: This topic was derived from articles that were searched and screened using the following evidence: PubMed, Google Scholar, and Sci-Hub.
Result: This study review is conducted to provide an overview of the effects of e-cigarettes vs tobacco cigarettes on fetal lung development. Based on evidence from articles, nicotine serves as a mediator between e-cigarettes and conventional cigarettes. Smokers often perceive e-cigarettes to be the safer option between the two. However, they are quite addictive due to their nicotine content, and vaping persists even during pregnancy, leading to respiratory disorders in offspring.
Conclusion: Hence, the study shows that e-cigarettes and regular tobacco cigarettes have a pathological influence on the fetus.
How to cite this article: Padamadan MJ, Nair A. Effects of Maternal Electronic Cigarette Smoking vs Tobacco Cigarette Smoking on Fetal Lung Development: A Narrative Review. Int J Infertil Fetal Med 2024;15(2):108-111.
Source of support: Nil
Conflict of interest: None
Keywords: Abnormal lung function, Effect of cigarette on lungs, Electronic cigarette, Electronic smoking, Fetal lung development, Maternal smokers, Pulmonary function, Tobacco cigarette.
BACKGROUND
Maternal smoking during gestation is a persistent public health problem, which has a detrimental impact on fetal lung or respiratory function.1 Smoking during pregnancy leads to preterm delivery, low birth weight, exposure of the cardiovascular system to harmful effects, as well as respiratory issues and instances of sudden infant death.2 There are various studies that reveal respiratory diseases that take place increasingly, where the newborn has been seen to have due to maternal smoking.1 Even though there is evidence that smoking during pregnancy has an aftermath on the fetus and newborn, this practice has been habituated globally and continues to remain a major worry. Approximately, 15–25% of mothers smoke during their pregnancy. Even though pregnancy impels a minority of women to halt the use of cigarettes briefly during the course of their gestation, mothers begin once more after they deliver their newborn. In spite of the present-day understanding of the outcome of smoking throughout pregnancy, there is an extremely low progression of decreasing smoking among pregnant females. Mothers under the use of smokeless tobacco give birth prematurely compared to mothers that don’t use tobacco (mean difference 6.2 days), there is a rise in the possibility of risk in preterm newborns by factor 1.4. The birth of a newborn before week 32 was 3.7 and before 28 weeks the birth of the newborn was about 7.2.3
The fetal lung undergoes development and it has several morphological stages.4 There are multiple changes seen in the fetal lungs during different gestational stages. There are five stages in the gestation period—the embryonic stage, which spans from weeks 0 to 6; the pseudoglandular stage, occurring from 6 to 16 weeks; the canalicular stage, lasting from 16 to 24 weeks; the saccular stage, encompassing weeks 24–40 (term); and the alveolar stage, which occurs after birth.5 Starting off from the embryonic stage, is the initial phase occurring right after conception. It’s when fetal lung development occurs, spanning from 0 to 6 weeks of gestation. Around the 5th week of gestation, when the mother comes into play, most major organs begin to form. The embryo measures 4 mm in length. At this stage, the lung begins to show development as a small bud-like formation from a small tube of cells called the foregut, which occurs earlier.6 Primarily, once the foregut is formed, it bifurcates into the anterior trachea and posterior esophagus, potentially leading to a tracheoesophageal fistula. Later, the trachea differentiates into the right and left bronchial buds, which are precursors of each lung. The bronchial walls are surrounded by mesenchymal cellular tissue, which develops at the bronchial buds and later differentiates to become muscle, connective tissue, and cartilage. During the pseudoglandular stage, spanning from around the 6th to the 16th week of gestation, the fetal lung begins to develop by branching out into two. The right side divides to form the upper, middle, and lower lobes of the right lung, while the left side, divides to form the upper and lower lobes of the left lung. Further division takes place throughout this stage.
By the end of the pseudoglandular stage, moving towards the next stage, the fetal lungs have developed all their main airways and smaller airways. In the canalicular stage, which occurs around the 16–24th week of gestation, the fetal lung subdivides and produces 8–32 bronchial segments. Thin air-blood barriers start to form, and surfactant production begins. During the saccular stage, which lasts until birth, formation of connective tissue between airspaces occurs, and surfactant undergoes further maturation. After birth, the lung structure remains immature, and the alveolar gas exchange system is not yet formed. Lastly, during the first 1–3 years of a toddler’s life, alveoli form during the alveolar stage, with gas exchange becoming similar to that of an adult lung.7
Electronic cigarettes are composed of various components such as a battery-operated device that uses a liquid solution as a dose of inhaled nicotine.8,9 E-cigarette is used as a substitute by people who smoke currently, formerly and who are new to smoking compared to regular cigarettes.10 E-cigarettes have become largely popular throughout the world with many users who are adolescents or mothers who see e-cigarettes as a safer option compared to combusted tobacco cigarettes.2 It includes nicotine, flavors, propylene glycol, and vegetable glycerine.10 E-cigarettes are encouraged to be less harmful compared to regular tobacco cigarettes because of the less harmful nicotine delivery.7 Many health effects have been detected because of the aerosol that’s produced in e-cigarettes. Different pulmonary conditions like lipoid pneumonia and diffuse alveolar hemorrhage are seen but at low rates. Symptoms mainly such as cough, shortness of breath, chest pain, fever, and fatigue are presented in a patient with e-cigarette or vaping-associated lung injury (EVALI).11
The leading cause of death in the world is primarily cigarette smoking. Regular tobacco cigarettes depend on the dose, individuals who are susceptible help determine the respiratory effect of smoking. Smoking increases the risk of causing cancer or it also involves lung, liver and colorectal. Tobacco cigarette smoking has shown results of injury to the fetal lung during prenatal development since there is a direct transport of nicotine to the fetus.12 Smokers who smoke for over 5 years or so show a deteriorating respiratory function that is seen to be more rapid than a normal respiratory function. Mostly, the risk would be of developing disability like chronic obstructive pulmonary disease or lung cancer. Smoking also is well known to aggravate airway reactivity and inflammation in asthma.13
Electronic cigarette smoking is extremely different from regular tobacco smoking, it contains dozens of chemicals that are not found in cigarette smoke. The smoke could cause pathological changes in the lungs. In pulmonary physiology, inhalation of e-cigarette aerosol causes increased airway activities, airway obstruction will be observed including inflammation and emphysema in the lungs. There is also a decrease in the vital capacity of the lungs.9
Maternal smoking has a huge impact on their reproductive abilities causing adverse effects on early embryo and fetal development. There were many studies that verified the negative impact on newborns during prenatal and postnatal growth the rise in the possibility of fetal morbidity and mortality their behavioral changes and the development of their cognitive function.3 Nicotine, which is a crucial component of tobacco cigarettes or e-cigarettes, is responsible for affecting lung development. The earliest effects of maternal smoking on fetal lung growth decrease forced expiratory flow which is between 25 and 75% of vital capacity; also the forced expiratory volume is heard only about three-fourths of a second.9
The major effects observed in the lung function of newborns with a maternal smoker include a reduction in forced expiratory flow and passive respiratory compliance. Infants are frequently hospitalized for pulmonary disorders, and there is an increased prevalence of early-life asthma and wheezing. The impact of nicotine, the major component in tobacco smoke responsible for fetal pulmonary maturation, appears to be mitigated by vitamin C supplements.1
This study aims to identify the effects of maternal e-cigarette smoking vs regular tobacco cigarette smoking on fetal lung development.
EFFECTS OF SMOKING ON THE FETAL LUNG DEVELOPMENT
Both tobacco cigarettes and e-cigarettes, which contain nicotine, have a significant impact on fetal lung development.
Lung Development
The typical progression begins with an initial bud, followed by five phases—embryonic, pseudoglandular, canalicular, saccular, and alveolar. This progression aids in understanding the association between the various stages of maturation and vascular development of the pulmonary structure, along with factors such as the environment, biology, and physical attributes, and how they interact. It also discusses the physiological and molecular evolution, observed and attempted through the coordination of various circumstances.4,5
Nicotine Delivery to an Individual
Nicotine, a drug found in tobacco, connects the brain with the body by sending rapid messages, which can lead to neurological abnormalities in newborns due to disruptions in neurotransmitter function. As a conclusion to this study, all forms of nicotine drugs should be counseled against and avoided by pregnant females. Some studies have shed light on nicotine delivery through electronic devices, which have gained popularity in recent years. Despite discussions of pulmonary disease in 2019, with patients presenting acute respiratory ailments linked to vaping, termed EVALI, this study reviewed the pathological findings associated with EVALI due to nicotine delivery, including various findings, pathological features, and treatment options. This study underscores the negative effects of EVALI observed in individuals.11
Tobacco Cigarettes and Their Effects
The increased pulmonary effects observed in the fetus and child’s respiratory development, as specified above, are due to maternal smoking during the gestation period, whether active or passive. The respiratory morbidities of infants increase, and lung health declines or is compromised. Several studies have indicated that fetal lung development is highly sensitive to the effects of in utero tobacco cigarettes, resulting in altered lung function at birth. These deficits often manifest as decreases in forced expiratory flows. A study focused on researching the harmful effects observed during pregnancy assessed mothers aged 18–44 for recognized harm. It demonstrated how e-cigarettes are relatively damaging compared to tobacco cigarettes, with percentages indicating them as less injurious (11.1%), equally injurious (51%), and more injurious (11.6%). Researchers also conducted a study highlighting the critical hazards of prenatal exposure to tobacco smoke, which raises infant morbidity and mortality rates. The study revealed that nicotine replacement therapy is a preferable method for managing these risks.1,2
Electronic Cigarettes and Their Effects
Studies discussing the use of electronic vaping products (EVPs) indicate that approximately half of adults perceive them to be as harmful as smoking a normal tobacco cigarette, while around a quarter of them are uncertain about the difference. These studies also reveal varying levels of perception regarding the damage caused by EVP vs tobacco cigarettes during pregnancy.2,8
E-CIGARETTES USAGE BEING RESEARCHED ON INDIVIDUALS OTHER THAN PREGNANT FEMALE
Researchers conducted a study by categorizing individuals based on the frequency of their use—daily, occasional, or experimental. Out of approximately nine studies conducted, four studies were deemed suitable for inclusion in this study, as they examined the effects of daily, occasional, and experimental use. This study also examined individuals who use e-cigarettes by reviewing their gender, socioeconomic status, and geographic location. It discovered that e-cigarettes are primarily used by present-day adult smokers, with a higher prevalence among men. The usage of e-cigarettes is particularly promoted among middle-aged or adult men who are already smokers. Another study indicates that adults who smoke for many years are more susceptible to developing pulmonary conditions such as lung cancer or chronic obstructive pulmonary disease. In conclusion, the understanding of the effects of e-cigarettes on pulmonary health is less comprehensive compared to that of tobacco cigarettes.8,10
Maternal Smokers Who Have Secondary Exposure to Smoking
The major focus is on newborns of maternal smokers who are exposed to nicotine and other harsh smoke, such as tobacco, in the uterus and their surrounding environment. Studies have highlighted the negative effects of secondhand smoke exposure on fetal lung function and various adverse effects seen due to smoke exposure during pregnancy. The study also suggests that tobacco cigarettes are damaging to newborns, while e-cigarettes appear to be perceived as less harmful devices for adolescents or long-time smokers to lean toward.9
Electronic Cigarettes Impact on the Newborn
The study by Gotts et al. aims to focus on the effect of e-cigarettes on newborn health, particularly chronic exposure. It educates on proper respiratory functions of airway circulation and aims to deepen pulmonary protection from foreign substances. The study discusses the various negative effects observed during the use of e-cigarettes, including those on the nose, mouth, throat, and airways.10
Smoking being Recorded
The primary goal of the study was to highlight tobacco cigarettes as the leading cause of preventable diseases and premature death. It discusses various recommended strategies for smokers, including documenting their smoking status, providing advice to quit, assisting them in quitting voluntarily, offering smoking cessation support, and ensuring follow-up and continuous support. Additionally, the study mentions that maternal smoking during the last 3 months of gestation increases the risk of preterm birth.
QUESTIONNAIRE ON THE SMOKING COMMUNITY
Research was conducted on the increasing use of electronic smoking, a nicotine delivery device, particularly among the young population. This is attributed to the fact that e-cigarettes lack many substances found in regular tobacco cigarettes. For this study, approximately 184 modified global health youth surveys were completed electronically or via paper. The survey included questions regarding age range, smoking status, and perceptions about tobacco cigarette smoking and e-cigarette smoking. In conclusion, of the 184 respondents to the questionnaire, approximately 68 were young adults, 55 were adults, and 61 were older adults. The study also revealed that out of the 109 respondents, at least one regular tobacco cigarette had been smoked, and 40 respondents had tried e-cigarettes.12
CONCLUSION
The utilization of e-cigarettes is recognized and practiced to be less damaging compared to conventional tobacco cigarettes. The chief element that makes tobacco cigarettes addictive is nicotine.12 The electronic smoking device has various absent substances that are not seen in conventional tobacco cigarettes.13 Electronic products are considered and believed to be a secure option than conventional cigarettes, mainly during high-risk circumstances such as, during pregnancy. Of all the users about 74% trust e-cigarette to be a much harmless alternative compared to tobacco cigarettes.2 Researchers have proven that mothers or women who smoke tobacco cigarettes or e-cigarettes as well as are exposed to environmental tobacco smoke have major phenotypic changes toward the pulmonary system of the fetus.14
Conventional or tobacco cigarettes are proven to be damaging to newborns.9 It has also been evident that e-cigarettes have been shown to negatively impact the fetal lung in multiple aspects such as the cellular aspect of the lungs, the organ’s physiology and the effects on the newborn’s immune system.10 While the fetus is in the uterus and moreover when the child is exposed to the smoke passively it causes several reactions toward the fetal health after they are born throughout their childhood. Although the effect of the nicotine transporting mechanism seems to be injurious, this acts as a start, as a combustible cigarette for adolescents.9
Mothers perceive e-cigarettes to be a much safer option compared to tobacco cigarettes and use them during the gestational period; e-cigarettes get rid of the use of any substances or deadly toxins that are present in tobacco, while they carry on the practice of the use of nicotine.12 There is an increase in the number of pregnant females than females who aren’t pregnant who confidently trust the fact that e-cigarettes are less damaging compared to tobacco cigarettes.2
Overall conclusion says that there are various downfalls that are observed in the lung development of the fetus due to the effects of the nicotine present in the e-cigarettes, other than tobacco being the link to the negative effects on the fetus.12 Few reviews have drawn closer, that a mother who consumes large amounts of smoke is related to the increase in stillbirth of the fetus, neonatal death, and perinatal death. There have also been reports and research on fetal growth is negatively impacted, which affects the fetus being delivered preterm.3
Through this study, we have discovered that the use of e-cigarettes is equally or much worse compared to tobacco cigarettes due to the nicotine content and the dosage that is present in it which causes a damaging effect on the offspring’s respiratory function and structure.
Limitations
There were no limitations in accessing any articles. None of the articles are in any other language other than English. None of the articles ranted on other organs or systems other than the respiratory system. The studies were only searched on maternal smokers. Studies were selected that spoke on e-cigarettes and tobacco cigarettes and not any other substance intake such as cocaine, marijuana, etc.
FUTURE SCOPE
A retrospective cohort can be taken using various outcome measures to assess the impact of smoking on the offspring.
ORCID
Aishwarya Nair https://orcid.org/0000-0002-2153-1439
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