Maternal smokeless tobacco use in Alaska Native women and singleton infant birth size

The invisible enemy: A systematic review and meta-analysis of maternal smokeless tobacco use as a risk factor for low birth weight

INTRODUCTION

Smokeless tobacco use is a growing public health concern, with potential adverse implications for foetal outcomes if consumed during pregnancy. Birth weight is an important predictive measure for health outcomes of a child throughout their lifespan. Despite extensive literature, it is unclear whether smokeless tobacco consumption during pregnancy has an adverse effect on birth weight. Hence, this review was conducted to determine whether an association exists between maternal smokeless tobacco consumption during pregnancy and birth weight of infants.

METHODS

Systematic literature search was performed in Medline (via PubMed), Embase, Scopus, and CINAHL with no restrictions on language or time until May 2024. All observational studies that examined the relationship between maternal smokeless tobacco use and low birth weight of infants were eligible for inclusion. Methodological quality of included studies was assessed using the Newcastle Ottawa Scale.

RESULTS

Thirty-three studies were eligible for the review, including twenty-eight cohort, three case-control and two cross-sectional studies. A statistically significant association between use of smokeless tobacco and low birth weight was reported in thirteen studies. Eleven studies reported a statistically significant reduction in mean birth weight in maternal smokeless tobacco users. Pooled estimates of eighteen studies with 733,061 participants showed that there was a statistically significant association (OR = 2.25 [1.63, 3.11] P<0.001); between maternal smokeless tobacco use during pregnancy and low birth weight. Subgroup analysis found a significant association between mishri consumption during pregnancy and low birth weight (n = 646 participants, OR = 10.98 [2.03, 59.34], P = 0.005), but not betel nut (n = 8007 participants, OR = 1.02 [0.84, 1.25]), betel quid (n = 483 participants, OR = 1.51 [0.47, 4.89]) or khat (n = 475 participants, OR = 1.41 [0.64-3.09]).

CONCLUSIONS

This review presents an association between maternal smokeless tobacco use and low birth weight, and reduction in mean birth weight. It is suggested that cessation and reduction of maternal smokeless tobacco use should receive specific attention within routine prenatal care.

IMPLICATIONS

The results of this study highlight the need for further preventive public health campaigns to create awareness about detrimental effects of smokeless tobacco on foetal outcomes. Patient education in the primary care setting will aid in promoting smokeless tobacco cessation prior to pregnancy.

Use of Smokeless Tobacco Before Conception and Its Relationship With Maternal and Fetal Outcomes of Pregnancy in Thatta, Pakistan: Findings From Women First Study

INTRODUCTION

Smokeless tobacco (SLT) consumption during pregnancy has adverse consequences for the mother and fetus. We aimed to investigate the effects of maternal pre-pregnancy SLT consumption on maternal and fetal outcomes in the district of Thatta, Pakistan.

AIMS AND METHODS

We conducted a secondary data analysis of an individual randomized controlled trial of preconception maternal nutrition. Study participants were women of reproductive age (WRA) residing in the district of Thatta, Pakistan. Participants were asked questions regarding the usage of commonly consumed SLT known as gutka (exposure variable). Study outcomes included maternal anemia, miscarriage, preterm births, stillbirths, and low birth weight. We performed a cox-regression analysis by controlling for confounders such as maternal age, education, parity, working status, body mass index, and geographic clusters.

RESULTS

The study revealed that 71.5% of the women reported using gutka, with a higher proportion residing in rural areas as compared with urban areas in the district of Thatta, Pakistan. In the multivariable analysis, we did not find a statistically significant association between gutka usage and anemia [(relative risk, RR: 1.04, 95% confidence interval, CI (0.92 to 1.16)], miscarriage [(RR: 1.08, 95% CI (0.75 to 1.54)], preterm birth [(RR: 1.37, 95% CI (0.64 to 2.93)], stillbirth [(RR: 1.02, 95% CI (0.39 to 2.61)], and low birth weight [(RR: 0.96, 95% CI (0.72 to 1.28)].

CONCLUSIONS

The study did not find an association between gutka usage before pregnancy and adverse maternal and fetal outcomes. In the future, robust epidemiological studies are required to detect true differences with a dose-response relationship between gutka usage both before and during pregnancy and adverse fetomaternal outcomes.

IMPLICATIONS

While most epidemiological studies conducted in Pakistan have focused on smoking and its adverse outcomes among males, none of the studies have measured the burden of SLT among WRA and its associated adverse outcomes. In addition, previously conducted studies have primarily assessed the effect of SLT usage during pregnancy rather than before pregnancy on adverse fetal and maternal outcomes. The current study is unique because it provides an insight into the usage of SLT among WRA before pregnancy and investigates the association between pre-pregnancy SLT usage and its adverse fetomaternal outcomes in rural Pakistan.

Dual use of cigarettes and electronic nicotine delivery systems during pregnancy and the risk of small for gestational age neonates

PURPOSE

The purpose of this study was to estimate the effect of cigarette smoking and electronic nicotine delivery systems (ENDS) use during pregnancy on small for gestational age (SGA).

METHODS

We used data from the 2016-2017 Arkansas Pregnancy Risk Assessment Monitoring System, estimated the risk ratio (RR) for SGA for maternal prenatal cigarette smoking-only use, cigarette smoking, and ENDS use (i.e., dual use), with no prenatal tobacco use as referent, accounting for the complex survey design. We also explored these effects for women who stopped smoking cigarettes during pregnancy among cigarette smokers and dual users.

RESULTS

Estimated adjusted RR for SGA for cigarette-only users was 1.7 (95% confidence interval [CI]: 1.1, 2.7), and 1.8 (95% CI: 1.0, 3.4) for dual users. These RR estimates increased after correcting for tobacco use misclassification. Women who were dual users (cigarette smokers and ENDS users) and continued using ENDS but stopped smoking cigarettes had an increased risk for SGA compared with nontobacco users, 3.2 (95% CI: 1.5, 6.6).

CONCLUSIONS

Our results in a population representative sample are consistent with the hypothesis that exposure to both maternal cigarette smoking and ENDS use increased the risk of SGA. Dual users still had an elevated risk of SGA after smoking cessation.

Association of maternal determinants with low birth weight babies in tea garden workers of Assam

AIM

This study was aimed to evaluate the association of maternal determinants with birth weight (BW) of babies in tea garden workers (TGW) and housewives (HW).

METHODS

A total of 175 subjects were recruited from Assam Medical College, Dibrugarh, India. In this cross-sectional study, maternal determinants, BW of babies and placental weight were explored in TGW (n = 102) and HW (n = 73). These factors were assessed and correlated by logistic regression models.

RESULTS

A higher incidence of low birth weight (LBW) was found in mothers working in the tea garden (48.04%) as compared to HW (10.96%). Activity of plucking of leaves in tea garden by women had a higher risk for LBW babies (adjusted odd ratio [AOR] 4.33, 95% confidence interval [CI] 1.38-13.57, P = 0.012) and decreased placental weight (AOR 11.42, 95% CI 1.18-126.02, P = 0.036) as compared to HW considered as reference group. Women who worked continuously in the tea garden during 9 months of pregnancy also revealed an elevated risk for LBW (AOR 5.32, 95% CI 1.34-21.09, P = 0.017).

CONCLUSION

This study suggests the activity of plucking of tea leaves by women is associated with LBW of babies and decreased placental weight. Particularly, if mothers worked continuously in the tea garden during 9 months of pregnancy, it also increased the risk of delivering LBW babies. This exploratory study provides an important platform for further prospective studies, which could be focused on the potential consequences of maternal occupational exposures during pregnancy on fetal development.

Ambient air pollution and markers of fetal growth: A retrospective population-based cohort study of 2.57 million term singleton births in China

BACKGROUNDS

Evidence is scarce on the relation between maternal exposure to ambient air pollution during pregnancy and fetal growth in developing countries. Moreover, the current evidence is inconsistent. We aimed to investigate the association of trimester-specific exposure to air pollution with risk of being born small for gestational age (SGA) and birth weight-markers of fetal growth-among Chinese term births.

METHODS

This retrospective population-based cohort study consisted of 2,567,457 singleton term live-births from January 1, 2014 to December 31, 2017 across 123 Chinese districts and counties. Personal exposure to ambient air pollutants including carbon monoxide (CO), sulfur dioxide (SO₂), nitrogen dioxide (NO₂), ozone (O₃), particulate matter with aerodynamic diameter < 2.5 μm (PM_2.5), and PM₁₀ was assigned using the inverse distance weighting spatial interpolation algorithm. Generalized estimating equations (GEE) logistic regression models were performed to estimate the associations between trimester-specific exposure to air pollution and risk of SGA or low birth weight (LBW), and GEE linear regression to examine the associations between the exposure and term birth weight, adjusting for maternal demographics, maternal cigarette smoking status during pregnancy, mode of delivery, gravidity, gestational age, year and month of conception, neonate's sex, and meteorological factors. Stratified and sensitivity analyses were also performed.

RESULTS

When mother exposed to ambient air pollutants over the entire pregnancy, per IQR increment (0.122 mg/m³) in ambient CO concentrations was associated with higher risk of SGA (odds ratio (OR) = 1.04, 95% confidence interval (CI): 1.02, 1.05) and reduced birth weight among term births (-5.95 g, 95% CI: -8.01, -3.89). This association was also pronounced in the second and third trimesters. Term birth weight was negatively associated with per IQR increase of O₃ (-3.52 g, 95% CI: -6.23, -0.81), PM_2.5 (-5.93 g, 95% CI: -8.36, -3.49) and PM₁₀ (-7.78 g, 95% CI: -10.41, -5.16) during the entire pregnancy, respectively. No significant association was detected between maternal exposure to air pollutants and term LBW. Effect estimates of heterogeneity suggested that maternal age and infant sex modified the impact of air pollution on birth weight.

CONCLUSIONS

The findings suggest that maternal exposure to air pollution during pregnancy is adversely affecting fetal growth. Further studies are warranted to integrate these findings and take clinical or public health interventions in pregnancy.

Trends in maternal use of snus and smoking tobacco in pregnancy. A register study in southern Norway

BACKGROUND

The use of tobacco products including Swedish snus (moist snuff) in pregnancy may cause adverse health outcomes. While smoking prevalence has decreased among fertile women in Norway, snus use has increased during the last years. We investigated whether these trends were reflected also during pregnancy in a population of women in Southern Norway.

METHODS

Data on smoking tobacco and snus use at three time points before and during pregnancy for 20,844 women were retrieved from the electronic birth record for the years 2012-2017. The results for the three-year period 2015-2017 were compared with a previously studied period 2012-2014. Prevalence and quit rates of tobacco use within groups of age, parity and education were reported. Within the same groups adjusted quit rates were analyzed using logistic regression. Mean birthweight and Apgar score of offspring were calculated for tobacco-users and non-users.

RESULTS

There was an increase of snus use before pregnancy from the period 2012-2014 to the period 2015-2017 from 5.1% (CI; 4.6 to 5.5) to 8.4% (CI; 7.8 to 8.9). Despite this, the use of snus during pregnancy did not increase from the first to the second period, but stabilized at 2.8% (CI; 2.5 to 3.2) in first trimester and 2.0% (CI; 1.7 to 2.2) in third trimester. Cigarette smoking decreased significantly both before and during pregnancy. Snus use and smoking during pregnancy were associated with a reduction in average birthweight, but no significant effects on Apgar scores. Odds ratios for quitting both snus and smoking tobacco during pregnancy were higher for women aged 25-34 years, for the primiparas and for those with a high level of education. Pregnant women were more likely to have quit tobacco use in the last time period compared to the first.

CONCLUSIONS

While smoking during pregnancy was decreasing, the use of snus remained constant, levelling off to around 3% in first trimester and 2% in third trimester. Approximately 25% of those that used snus, and 40% that smoked before pregnancy, continued use to the third trimester. This calls for a continuous watch on the use of snus and other nicotine products during pregnancy.

Developmental toxicity of nicotine: A transdisciplinary synthesis and implications for emerging tobacco products

While the health risks associated with adult cigarette smoking have been well described, effects of nicotine exposure during periods of developmental vulnerability are often overlooked. Using MEDLINE and PubMed literature searches, books, reports and expert opinion, a transdisciplinary group of scientists reviewed human and animal research on the health effects of exposure to nicotine during pregnancy and adolescence. A synthesis of this research supports that nicotine contributes critically to adverse effects of gestational tobacco exposure, including reduced pulmonary function, auditory processing defects, impaired infant cardiorespiratory function, and may contribute to cognitive and behavioral deficits in later life. Nicotine exposure during adolescence is associated with deficits in working memory, attention, and auditory processing, as well as increased impulsivity and anxiety. Finally, recent animal studies suggest that nicotine has a priming effect that increases addiction liability for other drugs. The evidence that nicotine adversely affects fetal and adolescent development is sufficient to warrant public health measures to protect pregnant women, children, and adolescents from nicotine exposure.

Determinants of Salivary Cotinine among Smokeless Tobacco Users: A Cross-Sectional Survey in Bangladesh

Introduction

More than 80% of all smokeless tobacco (ST) products in the world are consumed in South Asia; yet little is known about their consumption behaviour, addictiveness, and toxic properties. This paper, for the first time, describes associations between salivary cotinine concentrations among ST users in Bangladesh and their socio-demographic characteristics and tobacco use behaviours.

Methods

In a survey of ST users in Dhaka, Bangladesh, we purposively recruited 200 adults who were non-smokers but consumed ST on a regular basis. In-person interviews were conducted to obtain information about socio-demographic and ST use behaviours, and saliva samples were collected to measure cotinine concentration. Simple and multiple linear regression analyses were conducted to test associations between the log transformed salivary cotinine concentration and other study variables.

Results

The geometric mean of cotinine concentration among ST users was 380ng/ml (GSD:2). Total duration of daily ST use in months had a statistically significant association with cotinine concentration. Other ST use characteristics including type and quantity of ST use, swallowing of tobacco juice, urges and strength of urges and attempts to cut down on tobacco use were not found to be associated with cotinine concentration in a multivariable model.

Conclusion

This is the first report from Bangladesh studying cotinine concentration among ST users and it points towards high levels of addiction. This warrants effective tobacco control policies to help ST cessation and prevention.

The Effects of Chewing Betel Nut with Tobacco and Pre-pregnancy Obesity on Adverse Birth Outcomes Among Palauan Women

The small Pacific Island nation of Palau has alarmingly high rates of betel nut with tobacco use and obesity among the entire population including pregnant women. This study aimed to determine the effects of betel nut with tobacco use and pre-pregnancy obesity on adverse birth outcomes. This study used retrospective cohort data on 1171 Palauan women who gave birth in Belau National Hospital in Meyuns, Republic of Palau between 2007 and 2013. The exposures of interest were pre-pregnancy obesity and reported betel nut with tobacco use during pregnancy. The primary outcomes measured were preterm birth and low birth weight among full-term infants. A significantly increased risk for low birth weight among full-term infants was demonstrated among those women who chewed betel nut with tobacco during pregnancy when other known risk factors were controlled for. Additionally, pre-pregnancy obesity was associated with a significantly increased risk for preterm birth when other known risk factors were controlled for. Both betel nut with tobacco use and pre-pregnancy obesity were associated with higher risks for adverse birth outcomes. These findings should be used to drive public health efforts in Palau, as well as in other Pacific Island nations where these studies are currently lacking.

The Role of Nicotine in the Effects of Maternal Smoking during Pregnancy on Lung Development and Childhood Respiratory Disease. Implications for Dangers of E-Cigarettes

Use of e-cigarettes, especially among the young, is increasing at near-exponential rates. This is coupled with a perception that e-cigarettes are safe and with unlimited advertising geared toward vulnerable populations, the groups most likely to smoke or vape during pregnancy. There is now wide appreciation of the dangers of maternal smoking during pregnancy and the lifelong consequences this has on offspring lung function, including the increased risk of childhood wheezing and subsequent asthma. Recent evidence strongly supports that much of the effect of smoking during pregnancy on offspring lung function is mediated by nicotine, making it highly likely that e-cigarette use during pregnancy will have the same harmful effects on offspring lung function and health as do conventional cigarettes. In fact, the evidence for nicotine being the mediator of harm of conventional cigarettes may be most compelling for its effects on lung development. This raises concerns about both the combined use of e-cigarettes plus conventional cigarettes by smokers during pregnancy as well as the use of e-cigarettes by e-cigarette-only users who think them safe or by those sufficiently addicted to nicotine to not be able to quit e-cigarette usage during pregnancy. Thus, it is important for health professionals to be aware of the risks of e-cigarette usage during pregnancy, particularly as it pertains to offspring respiratory health.

Behaviour change intervention for smokeless tobacco cessation: its development, feasibility and fidelity testing in Pakistan and in the UK

BACKGROUND

People of South Asian-origin are responsible for more than three-quarters of all the smokeless tobacco (SLT) consumption worldwide; yet there is little evidence on the effect of SLT cessation interventions in this population. South Asians use highly addictive and hazardous SLT products that have a strong socio-cultural dimension. We designed a bespoke behaviour change intervention (BCI) to support South Asians in quitting SLT and then evaluated its feasibility in Pakistan and in the UK.

METHODS

We conducted two literature reviews to identify determinants of SLT use among South Asians and behaviour change techniques (BCTs) likely to modify these, respectively. Iterative consensus development workshops helped in selecting potent BCTs for BCI and designing activities and materials to deliver these. We piloted the BCI in 32 SLT users. All BCI sessions were audiotaped and analysed for adherence to intervention content and the quality of interaction (fidelity index). In-depth interviews with16 participants and five advisors assessed acceptability and feasibility of delivering the BCI, respectively. Quit success was assessed at 6 months by saliva/urine cotinine.

RESULTS

The BCI included 23 activities and an interactive pictorial resource that supported these. Activities included raising awareness of the harms of SLT use and benefits of quitting, boosting clients' motivation and self-efficacy, and developing strategies to manage their triggers, withdrawal symptoms, and relapse should that occur. Betel quid and Guthka were the common forms of SLT used. Pakistani clients were more SLT dependent than those in the UK. Out of 32, four participants had undetectable cotinine at 6 months. Fidelity scores for each site varied between 11.2 and 42.6 for adherence to content - maximum score achievable 44; and between 1.4 and 14 for the quality of interaction - maximum score achievable was 14. Interviews with advisors highlighted the need for additional training on BCTs, integrating nicotine replacement and reducing duration of the pre-quit session. Clients were receptive to health messages but most reported SLT reduction rather than complete cessation.

CONCLUSION

We developed a theory-based BCI that was also acceptable and feasible to deliver with moderate fidelity scores. It now needs to be evaluated in an effectiveness trial.

Systematic Review of Interventions for Racial/Ethnic-Minority Pregnant Smokers

INTRODUCTION

Large disparities exist in smoking rates during pregnancy by racial/ethnic status.

AIMS

The current review examined controlled studies that predominantly included racial/ethnic-minority pregnant smokers for providing smoking cessation treatment.

METHODS

Two authors independently conducted the literature searches in the standard databases using a combination of the keywords with minority, pregnancy, smoking, and cessation identifiers.

RESULTS

The searches identified nine articles that met the inclusion criteria. Only two studies exclusively targeted specific minority groups. Most of them provided some form of brief smoking cessation counseling, with two combining with incentives and one combining with pharmacotherapy. Two studies provided intensive cognitive interventions. Pregnant smokers of American Indian or Alaska Native, Hispanic subgroups, and Asian or Pacific Islander are under-studied.

CONCLUSIONS

Future studies to treat minority pregnant smokers could target under-studied minority groups and may need to directly and intensely target smoking behavior, address cultural and psychosocial issues in an individualized and comprehensive manner, and analyze cost-benefit of an intervention.

The Human Cost of Tobacco Chewing Among Pregnant Women in India: A Systematic Review and Meta-analysis

BACKGROUND

In India, smokeless tobacco (SLT) use among pregnant women is high and its adverse effects on pregnancy outcomes have not been properly documented in.

OBJECTIVES

To collate available evidence on the association between SLT use and three adverse pregnancy outcomes, i.e. low birth weight, preterm birth and stillbirth among women in India.

SEARCH STRATEGY

A systematic search was conducted in MEDLINE, IndMed, Web of Science, Google Scholar and major journals. Two authors independently reviewed the studies and extracted data.

SELECTION CRITERIA

Inclusion criteria were English articles published till December 2014, case control, case cohort or cohort, and exposure and outcome variables meeting predefined criteria. Exclusion criteria were case series, case reports, cross-sectional designs, risk estimate not restricted/adjusted for smoking with or without adjustment for other factors and duplicate data. Qualitative synthesis was followed by meta-analysis. Attributable burden was estimated using the population attributable fraction method.

MAIN RESULTS

Pooled odds ratio was significant for all three outcomes: low birth weight (1.88, 95 % CI 1.38, 2.54), preterm birth (1.39: 1.01, 1.91) and stillbirth (2.85: 1.62, 5.01). We found that 0.87 million low birth weight babies, 0.19 million preterm births and 0.12 million stillbirths occurring annually in India could be attributed to maternal SLT use.

CONCLUSION

There was a suggestive evidence of SLT use associated with adverse pregnancy outcomes among women in India. Further studies in this field are required to generate more conclusive evidence.

Hormonal contraception among electronic cigarette users and cardiovascular risk: a systematic review

BACKGROUND

Women who use combined hormonal contraceptives and cigarettes have an increased risk for cardiovascular (CV) events. We reviewed the literature to determine whether women who use hormonal contraceptives (HC) and electronic cigarettes (e-cigarettes) also have an increased risk.

STUDY DESIGN

Systematic review.

METHODS

We searched for articles reporting myocardial infarction (MI), stroke, venous thromboembolism, peripheral arterial disease or changes to CV markers in women using e-cigarettes and HC. We also searched for indirect evidence, such as CV outcomes among e-cigarette users in the general population and among HC users exposed to nicotine, propylene glycol or glycerol.

RESULTS

No articles reported on outcomes among e-cigarette users using HC. Among the general population, 13 articles reported on heart rate or blood pressure after e-cigarette use. These markers generally remained normal, even when significant changes were observed. In three studies, changes were less pronounced after e-cigarette use than cigarette use. One MI was reported among 1012 people exposed to e-cigarettes in these studies. One article on nicotine and HC exposure found both exposures to be significantly associated with acute changes to heart rate, though mean heart rate remained normal. No articles on propylene glycol or glycerol and HC exposure were identified.

CONCLUSION

We identified no evidence on CV outcomes among e-cigarette users using HC. Limited data reporting mostly acute outcomes suggested that CV events are rare among e-cigarette users in the general population and that e-cigarettes may affect heart rate and blood pressure less than conventional cigarettes. There is a need for research assessing joint HC and e-cigarette exposure on clinical CV outcomes.

Global burden of disease due to smokeless tobacco consumption in adults: analysis of data from 113 countries

BACKGROUND

Smokeless tobacco is consumed in most countries in the world. In view of its widespread use and increasing awareness of the associated risks, there is a need for a detailed assessment of its impact on health. We present the first global estimates of the burden of disease due to consumption of smokeless tobacco by adults.

METHODS

The burden attributable to smokeless tobacco use in adults was estimated as a proportion of the disability-adjusted life-years (DALYs) lost and deaths reported in the 2010 Global Burden of Disease study. We used the comparative risk assessment method, which evaluates changes in population health that result from modifying a population's exposure to a risk factor. Population exposure was extrapolated from country-specific prevalence of smokeless tobacco consumption, and changes in population health were estimated using disease-specific risk estimates (relative risks/odds ratios) associated with it. Country-specific prevalence estimates were obtained through systematically searching for all relevant studies. Disease-specific risks were estimated by conducting systematic reviews and meta-analyses based on epidemiological studies.

RESULTS

We found adult smokeless tobacco consumption figures for 115 countries and estimated burden of disease figures for 113 of these countries. Our estimates indicate that in 2010, smokeless tobacco use led to 1.7 million DALYs lost and 62,283 deaths due to cancers of mouth, pharynx and oesophagus and, based on data from the benchmark 52 country INTERHEART study, 4.7 million DALYs lost and 204,309 deaths from ischaemic heart disease. Over 85 % of this burden was in South-East Asia.

CONCLUSIONS

Smokeless tobacco results in considerable, potentially preventable, global morbidity and mortality from cancer; estimates in relation to ischaemic heart disease need to be interpreted with more caution, but nonetheless suggest that the likely burden of disease is also substantial. The World Health Organization needs to consider incorporating regulation of smokeless tobacco into its Framework Convention for Tobacco Control.

Vitamin C supplementation ameliorates the adverse effects of nicotine on placental hemodynamics and histology in nonhuman primates

OBJECTIVE

We previously demonstrated that prenatal nicotine exposure decreases neonatal pulmonary function in nonhuman primates, and maternal vitamin C supplementation attenuates these deleterious effects. However, the effect of nicotine on placental perfusion and development is not fully understood. This study utilizes noninvasive imaging techniques and histological analysis in a nonhuman primate model to test the hypothesis that prenatal nicotine exposure adversely effects placental hemodynamics and development but is ameliorated by vitamin C.

STUDY DESIGN

Time-mated macaques (n = 27) were divided into 4 treatment groups: control (n = 5), nicotine only (n = 4), vitamin C only (n = 9), and nicotine plus vitamin C (n = 9). Nicotine animals received 2 mg/kg per day of nicotine bitartrate (approximately 0.7 mg/kg per day free nicotine levels in pregnant human smokers) from days 26 to 160 (term, 168 days). Vitamin C groups received ascorbic acid at 50, 100, or 250 mg/kg per day with or without nicotine. All underwent placental dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) at 135-140 days and Doppler ultrasound at 155 days to measure uterine artery and umbilical vein velocimetry and diameter to calculate uterine artery volume blood flow and placental volume blood flow. Animals were delivered by cesarean delivery at 160 days. A novel DCE-MRI protocol was utilized to calculate placental perfusion from maternal spiral arteries. Placental tissue was processed for histopathology.

RESULTS

Placental volume blood flow was significantly reduced in nicotine-only animals compared with controls and nicotine plus vitamin C groups (P = .03). Maternal placental blood flow was not different between experimental groups by DCE-MRI, ranging from 0.75 to 1.94 mL/mL per minute (P = .93). Placental histology showed increased numbers of villous cytotrophoblast cell islands (P < .05) and increased syncytiotrophoblast sprouting (P < .001) in nicotine-only animals, which was mitigated by vitamin C.

CONCLUSION

Prenatal nicotine exposure significantly decreased fetal blood supply via reduced placental volume blood flow, which corresponded with placental histological findings previously associated with cigarette smoking. Vitamin C supplementation mitigated the harmful effects of prenatal nicotine exposure on placental hemodynamics and development, suggesting that its use may limit some of the adverse effects associated with smoking during pregnancy.

Is there evidence for potential harm of electronic cigarette use in pregnancy?

BACKGROUND

Use of electronic cigarettes (e-cigarettes) and other nicotine containing products is increasing among women of reproductive age. The short- and long-term effects of these products on both mother and fetus are unknown.

METHODS

Because e-cigarettes are nicotine delivery systems, we sought to conduct a comprehensive review of the effects of nicotine on the fetus.

RESULTS

In utero nicotine exposure in animal models is associated with adverse effects for the offspring lung, cardiovascular system and brain. In the lung, this included reduced surface area, weight, and volume, as well as emphysema-like lesions. In adulthood, exposed offspring demonstrate elevated blood pressure and increased perivascular adipose tissue. In the brain, exposure alters offspring serotonergic, dopaminergic, and norepinephrine networks, which in turn are associated with behavioral and cognitive impairments. We also review current data on the lack of efficacy of nicotine replacement therapy in pregnant women, and highlight different nicotine containing products such as snuff, snus, and hookah.

CONCLUSION

We conclude that no amount of nicotine is known to be safe during pregnancy, and studies specifically addressing this risk are crucial and an imminent public health issue.

Smokeless tobacco use in pregnancy: an integrative review of the literature

OBJECTIVES

To systematically critique and summarise the available evidence on the outcomes of smokeless tobacco use in pregnancy to inform the public health response.

METHODS

In March 2013, a search was conducted of observational studies where the exposure to smokeless tobacco during pregnancy and maternal, placental and/or neonatal outcomes was assessed. Two reviewers extracted data and completed quality assessment of the literature utilizing the Agency for Healthcare Research and Quality criteria (West et al. 2002).

RESULTS

The search resulted in 211 articles, 21 (10%) of which met the final criteria for integrative review. Ten (10) of the studies are from India, seven (7) from Sweden, two (2) from Alaska and one (1) each from South Africa and Pakistan.

CONCLUSIONS

Many studies lacked sufficient power to estimate precise risks. Most reports were hindered by imprecise measures of exposure and lack of confounding variable control. However, there were indications that maternal smokeless tobacco use increases rates of stillbirth, low birth weight and alters the male:female live birth ratio. Maternal smokeless tobacco use may not be safe for mother or foetus.

Smokeless tobacco control policies in South Asia: a gap analysis and recommendations

INTRODUCTION

Almost a fifth of the world's tobacco is consumed in smokeless form. Its consumption is particularly common in South Asia, where an increasing array of smokeless tobacco (SLT) products is widely available. Mindful of the growing public health threat from SLT, a group of international academics and policy makers recently gathered to identify policy and knowledge gaps and proposed strategies to address these.

METHODS

We reviewed key policy documents and interviewed policy makers and representatives of civil society organizations in 4 South Asian countries: Bangladesh, India, Nepal, and Pakistan. We explored if SLT features in existing tobacco control policies and, if so, the extent to which these are implemented and enforced. We also investigated barriers to effective policy formulation and implementation. The findings were presented at an international meeting of experts and were refined in the light of the ensuing discussion in order to inform policy and research recommendations.

RESULTS

We found that the existing SLT control policies in these 4 South Asian countries were either inadequate or poorly implemented. Taxes were low and easily evaded; regulatory mechanisms, such as licensing and trading standards, either did not exist or were inadequately enforced to regulate the composition and sales of such products; and there was little or no cessation support for those who wanted to quit.

CONCLUSIONS

Limited progress has been made so far to address the emerging public health threat posed by SLT consumption in South Asia. International and regional cooperation is required to advocate for effective policy and to address knowledge gaps.

The effect of Swedish snuff (snus) on offspring birthweight: a sibling analysis

Current observational evidence indicates that maternal smoking during pregnancy is associated with reduced birthweight in offspring. However, less is known about the effect of smokeless tobacco on birthweight and about the possible mechanisms involved in this relationship. This paper studies the effect of Swedish smokeless tobacco (snus) on offspring birthweight comparing the results obtained from a conventional linear regression analysis and from a quasi-experimental sibling design using a multilevel linear regression analysis. From the Swedish Medical Birth Register, we investigated 604,804 singletons born between 2002 and 2010. From them, we isolated 8,861 siblings from 4,104 mothers with discrepant snus-use habits (i.e., women who had at least one pregnancy during which they used snus and at least one other pregnancy in which they did not). The conventional analysis shows that continuous snus use throughout the pregnancy reduces birthweight in 47 g while quitting or relapsing snus has a minor and statistically non-significant effect (−6 g and −4 g, respectively). However, using a sibling analysis the effect observed for mothers who continue to use snus during pregnancy is less intense than that observed with previous conventional analyses (−20 g), and this effect is not statistically significant. Sibling analysis shows that quitting or relapsing snus use after the first trimester slightly reduces birthweight (14 g).However, this small change is not statistically significant. The sibling analysis provides strong causal evidence indicating that exposure to snus during pregnancy has a minor effect on birthweight reduction. Our findings provide a new piece of causal evidence concerning the effect of tobacco on birthweight and support the hypothesis that the harmful effect of smoking on birthweight is not mainly due to nicotine.

Tobacco and areca nut chewing--reproductive impairments: an overview

A large number of people are using smokeless tobacco and areca nut worldwide. Sufficient data on tobacco smoking have harmful effect on human health and reproduction is available. However, data on the smokeless tobacco and areca nut use on human reproduction is scanty. This overview is an attempt to compose on the consumption of smokeless tobacco and areca nut on human reproduction and some relevant experimental data were also included. The existing studies suggest that tobacco and areca nut chewing alone, together or with other ingredients had reproductive toxic potential. Pregnant women using smokeless tobacco during pregnancy also had adverse effect on pregnancy and its outcome. Thus pregnant women must avoid consumption of any mixture containing areca nut and tobacco in order to protect the pregnancy and outcome. The data suggest that smokeless tobacco use is also harmful as smoking for reproduction and use of areca nut might have further compounded the problem.

Changes in snuff and smoking habits in Swedish pregnant women and risk for small for gestational age births

OBJECTIVE

To examine associations between antenatal exposure to Swedish oral moist snuff (which includes essentially only nicotine) and to smoking and risks of small-for-gestational-age (SGA) births and to compare risks among women who stopped or continued using snuff or smoking during pregnancy.

DESIGN

Population-based cohort study.

SETTING

Sweden.

POPULATION

All live singleton births in Sweden 1999-2010.

METHODS

Odds ratios (OR) with 95% confidence intervals (CI) were calculated using multiple logistic regression analysis.

MAIN OUTCOME MEASURES

SGA birth, also stratified into preterm (≤36 weeks of gestation) and term (≥37 weeks of gestation) SGA births.

RESULTS

Compared with non-tobacco users in early pregnancy, snuff users and above all smokers in early pregnancy had increased risks of SGA births: adjusted ORs (95% CI) were 1.26 (1.09-1.46) and 2.55 (2.43-2.67), respectively). Snuff use had, if anything, a stronger association with preterm SGA than term SGA, whereas the opposite was true for smoking. Compared with non-tobacco users, women who stopped using snuff before their first visit to antenatal care had no increased risks of preterm or term SGA, and women who stopped using snuff later during pregnancy had no increased risk of term SGA. Smoking cessation early in pregnancy was associated with a larger reduction in risk than smoking cessation later in pregnancy.

CONCLUSIONS

As both smoking and snuff use influence risk of SGA, both nicotine but above all tobacco combustion products are involved in the mechanisms by which maternal smoking increases the risk of SGA.