Use of nicotine replacement therapy during pregnancy and stillbirth: a cohort study

Nicotine Use During Pregnancy: Cessation and Treatment Strategies

Abstract

The use of tobacco and nicotine products during pregnancy is known to increase the risk of adverse effects on the fetus. Increased education and research have resulted in greater rates of smoking cessation during pregnancy, with a decline from 13.2% of pregnant individuals smoking in 2006 to 7.2% in 2016. However, smoking while pregnant still proves to be a prevalent issue that is associated with numerous adverse outcomes, including low birth weight, preterm birth, and developmental delays. Smoking cessation before or during pregnancy can help mitigate these effects, but the appropriate treatment can be challenging to ascertain. Accordingly, clinicians should look to provide individualized care composed of behavioral counseling in conjunction with pharmacotherapies when indicated, combined with ongoing support and education.

Modulation of preeclampsia by the cholinergic anti-inflammatory pathway: Therapeutic perspectives

The cholinergic anti-inflammatory pathway (CAP) is vital for the orchestration of the immune and inflammatory responses under normal and challenged conditions. Over the past two decades, peripheral and central circuits of CAP have been shown to be critically involved in dampening the inflammatory reaction in a wide array of inflammatory disorders. Additionally, emerging evidence supports a key role for CAP in the regulation of the female reproductive system during gestation as well as in the advent of serious pregnancy-related inflammatory insults such as preeclampsia (PE). Within this framework, the modulatory action of CAP encompasses the perinatal maternal and fetal adverse consequences that surface due to antenatal PE programming. Albeit, a considerable gap still exists in our knowledge of the precise cellular and molecular underpinnings of PE/CAP interaction, which hampered global efforts in safeguarding effective preventive or therapeutic measures against PE complications. Here, we summarize reports in the literature regarding the roles of peripheral and reflex cholinergic neuroinflammatory pathways of nicotinic acetylcholine receptors (nAChRs) in reprogramming PE complications in mothers and their progenies. The possible contributions of α7-nAChRs, cholinesterases, immune cells, adhesion molecules, angiogenesis, and endothelial dysfunction to the interaction have also been reviewed.

Fetal safety of nicotine replacement therapy in pregnancy: systematic review and meta-analysis

BACKGROUND AND AIMS

Smoking in pregnancy causes substantial avoidable harm to mothers and offspring; nicotine replacement therapy (NRT) may prevent this, and is used to help women to quit. A recently updated Cochrane Review of randomized controlled trials (RCTs) investigating impacts of NRT in pregnancy focuses primarily on efficacy data, but also reports adverse impacts from NRT. Here we identify and summarize NRT impacts on adverse pregnancy outcomes reported in non-randomized controlled trials (non-RCTs).

METHODS

Systematic reviews and meta-analyses of RCTs and non-RCT studies of NRT in pregnancy, with design-specific risk of bias assessment and grading of recommendations, assessment, development and evaluations (GRADE) criteria applied to selected outcomes.

FINDINGS

Relevant Cochrane Review findings are reported alongside those from this new review. Seven RCTs were included; n = 2340. Nine meta-analyses were performed; non-statistically significant estimates indicated potentially reduced risk from NRT compared with smoking for mean birth weight, low birth weight, preterm birth, intensive care admissions, neonatal death, congenital anomalies and caesarean section and potentially increased risks for miscarriage and stillbirth. GRADE assessment for mean birth weight and miscarriage outcomes indicated 'low' confidence in findings. Twenty-three non-RCTs were included; n = 931 163. Eleven large studies from five routine health-care cohorts reported clinical outcomes; 12 small studies investigated mainly physiological outcomes within in-patient women given NRT. Findings from meta-analyses for congenital anomalies, stillbirth and preterm birth were underpowered and not in a consistent direction; GRADE assessment of confidence in findings was 'very low'. Routine health-care studies were of higher quality, but implications of reported findings were unclear as there was inadequate measurement and reporting of women's smoking.

CONCLUSIONS

Available evidence from randomized controlled trials and non-randomized comparative studies does not currently provide clear evidence as to whether maternal use of nicotine replacement therapy during pregnancy is harmful to the fetus.

Early Life Exposure to Nicotine: Postnatal Metabolic, Neurobehavioral and Respiratory Outcomes and the Development of Childhood Cancers

Cigarette smoking during pregnancy is associated with numerous obstetrical, fetal, and developmental complications, as well as an increased risk of adverse health consequences in the adult offspring. Nicotine replacement therapy and electronic nicotine delivery systems (e-cigarettes) have been developed as a pharmacotherapy for smoking cessation and are considered safer alternatives for women to smoke during pregnancy. The safety of nicotine replacement therapy use during pregnancy has been evaluated in a limited number of short-term human trials, but there is currently no information on the long-term effects of developmental nicotine exposure in humans. However, animal studies suggest that nicotine alone may be a key chemical responsible for many of the long-term effects associated with maternal cigarette smoking on the offspring and increases the risk of adverse neurobehavioral outcomes, dysmetabolism, respiratory illness, and cancer. This review will examine the long-term effects of fetal and neonatal nicotine exposure on postnatal health.

Potential effects of using non-combustible tobacco and nicotine products during pregnancy: a systematic review

Background

The range of risk reduced alternatives to smoking tobacco is increasing and so is use among pregnant women. The substantial harms of smoking during pregnancy are well established and there is reason to believe that nicotine alone is somewhat harmful. Differences in the exposure chemistry strongly suggest that the effects of using smoke-free nicotine products (including pharmaceutical nicotine products, smokeless tobacco, and electronic cigarettes containing nicotine) fall somewhere in the range between zero risk to the risk from smoking. How much lower risk these consumption choices are in terms of pregnancy outcomes, however, remains uncertain.

Methods

We reviewed the literature on smoke-free nicotine and tobacco product exposure and birth-outcome endpoints. Studies were included if they compared outcomes to either no nicotine use or smoking. We searched Google Scholar using broad search terms and additional articles were snowballed from citations. We report what could be learned from each study, given its methods.

Results

Of the 21 studies reviewed, 12 reported on the use of nicotine replacement therapies, 7 on Swedish snus, 1 on Alaskan iq’mik, and 1 on e-cigarettes. The range of results tends to support the prediction that smoke-free product use during pregnancy probably increases the risk of some negative birth outcomes, but that any effect is less than that from smoking. However, the limitations of epidemiology are such that no more-precise a conclusion is possible.

Discussion

The available epidemiology does not change our prior beliefs, based on other evidence and knowledge, that the risks from smoke-free nicotine and tobacco are lower than those for smoking, though it suggests they are non-zero. However, it also demonstrates that the epidemiology is unlikely to provide precise quantitative estimates. This is not just a matter of lack of studies; given the inherent limitation of these studies, doubling or tripling the corpus of available studies would add little precision. For the foreseeable future, decisions about using these products will need to be made based on rough estimates, based on a variety of forms of evidence, and qualitative comparisons.

Use of smoking cessation pharmacotherapies during pregnancy is not associated with increased risk of adverse pregnancy outcomes: a population-based cohort study

BACKGROUND

Varenicline, bupropion and nicotine replacement therapy (NRT) are three effective pharmacotherapies for smoking cessation, but data about their safety in pregnancy are limited. We assessed the risk of adverse perinatal outcomes and major congenital anomalies associated with the use of these therapies in pregnancy in Australia.

METHODS

Perinatal data for 1,017,731 deliveries (2004 to 2012) in New South Wales and Western Australia were linked to pharmaceutical dispensing, hospital admission and death records. We identified 97,875 women who smoked during pregnancy; of those, 233, 330 and 1057 were exposed to bupropion, NRT and varenicline in pregnancy, respectively. Propensity scores were used to match exposed women to those who were unexposed to any smoking therapy (1:10 ratio). Propensity scores and gestational age at exposure were used to match varenicline-exposed to NRT-exposed women (1:1 ratio). Time-dependent Cox proportional hazards models estimated hazard ratios (HR) with 95% confidence intervals (95% CI) for any adverse perinatal event (a composite of 10 unfavourable maternal and neonatal outcomes) and any major congenital anomaly.

RESULTS

The risk of any adverse perinatal event was not significantly different between bupropion-exposed and unexposed women (39.2% versus 39.3%, HR 0.93, 95% CI 0.73-1.19) and between NRT-exposed and unexposed women (44.8% vs 46.3%, HR 1.02, 95% CI 0.84-1.23), but it was significantly lower in women exposed to varenicline (36.9% vs 40.1%, HR 0.86, 95% CI 0.77-0.97). Varenicline-exposed infants were less likely than unexposed infants to be born premature (6.5% vs 8.9%, HR 0.72, 95% CI 0.56-0.92), be small for gestational age (11.4% vs 15.4%, HR 0.68, 95% CI 0.56-0.83) and have severe neonatal complications (6.6% vs 8.2%, HR 0.74, 95% CI 0.57-0.96). Among infants exposed to varenicline in the first trimester, 2.9% had a major congenital anomaly (3.5% in unexposed infants, HR 0.91, 95% CI 0.72-1.15). Varenicline-exposed women were less likely than NRT-exposed women to have an adverse perinatal event (38.7% vs 51.4%, HR 0.58, 95% CI 0.33-1.05).

CONCLUSIONS

Pregnancy exposure to smoking cessation pharmacotherapies does not appear to be associated with an increased risk of adverse birth outcomes. Lower risk of adverse birth outcomes in varenicline-exposed pregnancies is inconsistent with recommendations that NRT be used in preference to varenicline.

Stillbirth Among Women Prescribed Nicotine Replacement Therapy in Pregnancy: Analysis of a Large UK Pregnancy Cohort

INTRODUCTION

We aimed to compare risk of stillbirth between maternal smokers and those prescribed nicotine replacement therapy (NRT) during pregnancy.

AIMS AND METHODS

We conducted a cross-sectional analysis on a pregnancy cohort of 220,630 singleton pregnancies ending in live or stillbirth between 2001 and 2012 from The Health Improvement Network UK general practice database. Women were categorized into three groups: NRT (prescribed during pregnancy or 1 month before conception); smokers; and controls (nonsmokers without a pregnancy NRT prescription). We calculated Odds ratios (OR) and corresponding 95% confidence intervals (CI) for stillbirth in the NRT group and smokers compared to controls.

RESULTS

A total of 805 pregnancies ended in stillbirth (3.6/1000 births). Absolute risks of stillbirth in NRT and smoker groups were both 5/1000 births compared with 3.5/1000 births in the control group. Compared with the control group, the adjusted odds of stillbirth in the NRT group was not statistically significant (OR = 1.35, 95% CI 0.91 to 2.00), although it was similar in magnitude to that in the smokers group (OR = 1.41, 95% CI 1.13 to 1.77).

CONCLUSIONS

We found no evidence of a statistically significant association between being prescribed NRT during pregnancy and odds of stillbirth compared with nonsmoking women. Although our study had much larger numbers than any previously, an even larger study with biochemically validated smoking outcome data and close monitoring of NRT use throughout pregnancy is required to exclude effects on findings of potential exposure misclassification.

Impact of Nicotine Replacement and Electronic Nicotine Delivery Systems on Fetal Brain Development

Maternal tobacco smoking during pregnancy remains a major public health issue. The neurotoxic properties of nicotine are associated with fetal neurodevelopmental disorders and perinatal morbimortality. Recent research has demonstrated the effects of nicotine toxicity on genetic and epigenetic alterations. Smoking cessation strategies including nicotine replacement therapy (NRT) and electronic nicotine delivery systems (ENDS) show lack of clear evidence of effectiveness and safety in pregnant women. Limited trials using randomized controls concluded that the intermittent use formulation of NRT (gum, sprays, inhaler) in pregnant women is safe because the total dose of nicotine delivered to the fetus is less than continuous-use formulations (transdermal patch). Electronic nicotine delivery systems (ENDS) were hyped as a safer alternative during pregnancy. However, refill liquids of ENDS are suspected to be cytotoxic for the fetus. Animal studies revealed the impact of ENDS on neural stem cells, showing a similar risk of pre- and postnatal neurobiological and neurobehavioral disorders to that associated with the exposure to traditional tobacco smoking during early life. There is currently no clear evidence of impact on fetal brain development, but recent research suggests that the current guidelines should be reconsidered. The safety of NRT and ENDS is increasingly being called into question. In this review, we discuss the special features (pharmacodynamics, pharmacokinetics, and metabolism) of nicotine, NRT, and ENDS during pregnancy and postnatal environmental exposure. Further, we assess their impact on pre- and postnatal neurodevelopment.

Biological effects of nicotine exposure: A narrative review of the scientific literature

The emergence of new tobacco heating products and electronic nicotine delivery systems (ENDS) is changing the way humans are exposed to nicotine. The purpose of this narrative review is to provide a broad overview of published scientific literature with respect to the effects of nicotine on three key health-related areas: 1) cardiovascular risk, 2) carcinogenesis and 3) reproductive outcomes. These areas are known to be particularly vulnerable to the effects of cigarette smoke, and in addition, nicotine has been hypothesized to play a role in disease pathogenesis. Acute toxicity will also be discussed. The literature to February 2019 suggests that there is no increased cardiovascular risk of nicotine exposure in consumers who have no underlying cardiovascular pathology. There is scientific consensus that nicotine is not a direct or complete carcinogen, however, it remains to be established whether it plays some role in human cancer propagation and metastasis. These cancer progression pathways have been proposed in models in vitro and in transgenic rodent lines in vivo but have not been demonstrated in cases of human cancer. Further studies are needed to determine whether nicotine is linked to decreased fertility in humans. The results from animal studies indicate that nicotine has the potential to act across many mechanisms during fetal development. More studies are needed to address questions regarding nicotine exposure in humans, and this may lead to additional guidance concerning new ENDS entering the market.

Cardiovascular, carcinogenic and reproductive effects of nicotine exposure: A narrative review of the scientific literature

The emergence of new tobacco heating products and electronic nicotine delivery systems (ENDS) is changing the way humans are exposed to nicotine. The purpose of this narrative review is to provide a broad overview of published scientific literature with respect to the effects of nicotine on three key health-related areas: 1) cardiovascular risk, 2) carcinogenesis and 3) reproductive outcomes. These areas are known to be particularly vulnerable to the effects of cigarette smoke, and in addition, nicotine has been hypothesized to play a role in disease pathogenesis. Acute toxicity will also be discussed. The literature to February 2019 suggests that there is no increased cardiovascular risk of nicotine exposure in consumers who have no underlying cardiovascular pathology. There is scientific consensus that nicotine is not a direct or complete carcinogen, however, it remains to be established whether it plays some role in human cancer propagation and metastasis. These cancer progression pathways have been proposed in models in vitro and in transgenic rodent lines in vivo but have not been demonstrated in cases of human cancer. Further studies are needed to determine whether nicotine is linked to decreased fertility in humans. The results from animal studies indicate that nicotine has the potential to act across many mechanisms during fetal development. More studies are needed to address questions regarding nicotine exposure in humans, and this may lead to additional guidance concerning new ENDS entering the market.

An update on prevalence and risk of snus and nicotine replacement therapy during pregnancy and breastfeeding

AIM

In parallel with falling smoking rates, use of the oral moist tobacco product snus increases among women in reproductive age. We report an update on prevalence and effects of maternal use of snus and nicotine replacement therapy (NRT) during pregnancy and breastfeeding.

METHODS

A literature search of human studies in Medline, PubMed and EMBASE was conducted from September 2016 to May 2018, with stepwise screening of abstracts and subsequent relevant full-text papers for inclusion in Scandinavian and English languages.

RESULTS

Based on three studies, the prevalence of snus use in pregnancy was up to 3.4% in the first trimester and 2.1% in the third trimester. In 12 studies, we found increased risk of several adverse effects, especially preterm delivery, stillbirth and small for gestational age associated with maternal snus use during pregnancy. Knowledge on effects of NRT during pregnancy was conflicting and inconclusive in 10 studies. We did not identify any studies on prevalence or potential health effects of snus or NRT during breastfeeding.

CONCLUSION

Few studies with updated data on the prevalence and adverse health effects of maternal use of snus and NRT during pregnancy were found. No studies during breastfeeding were identified.

Comparison of nicotine exposure during pregnancy when smoking and abstinent with nicotine replacement therapy: systematic review and meta-analysis

BACKGROUND AND AIMS

Smoking during pregnancy is strongly associated with negative pregnancy and perinatal outcomes. Some guidelines recommend nicotine replacement therapy (NRT) for smoking cessation during pregnancy, but adherence with NRT is generally poor and could be partially explained by nicotine-related safety concerns. We compared pregnant women's cotinine and nicotine exposures from smoking with those when they were abstinent from smoking and using NRT.

DESIGN

Systematic review with meta-analysis and narrative reporting. Twelve studies were included: in most, only one type of NRT was used. Seven were quality-assessed and judge of variable quality.

SETTING

Studies from any setting that reported nicotine or cotinine levels when smoking and later when abstinent and using NRT.

PARTICIPANTS

Pregnant women who smoked and became abstinent but used NRT either in a cessation study or in a study investigating other impacts of NRT.

MEASUREMENTS

We quality-assessed longitudinal cohort studies using a modified version of the Newcastle-Ottawa scale. For meta-analysis, we used mean within-person differences in cotinine or nicotine levels when smoking and at later follow-up when abstinent and using NRT. Where such data were not available, we calculated differences in group mean levels and reported these narratively, indicating where data were not completely longitudinal.

FINDINGS

Of the 12 included studies, four cotinine-measuring studies (n = 83) were combined in a random effects meta-analysis; the pooled estimate for the mean difference (95% confidence intervals) in cotinine levels between when women were smoking and abstinent but using NRT was 75.3 (57.1 to 93.4) ng/ml (I²  = 42.1%, P = 0.11). Of eight narratively-described studies, six reported lower cotinine and/or nicotine levels when abstinent and using NRT; two had mixed findings, with higher levels when abstinent but using NRT reported from at least one assay time-point.

CONCLUSIONS

Pregnant women who use nicotine replacement therapy instead of smoking reduce their nicotine exposure.

Nicotine replacement therapy for smoking cessation during pregnancy

Nicotine replacement therapy (NRT) is recommended in current Australian clinical guidelines for pregnant women who are unable to quit smoking unassisted. Clinicians report low levels of prescribing NRT during pregnancy, due to safety concerns and low levels of confidence in their ability to prescribe NRT. Animal models show that nicotine is harmful to the fetus, especially for brain and lung development, but human studies have not found any harmful effects on fetal and pregnancy outcomes. Studies of efficacy and effectiveness in the real world suggest that NRT use during pregnancy increases smoking cessation rates. These rates may be hampered by the fact that studies so far have used an NRT dose that does not adequately account for the higher nicotine metabolism during pregnancy and, therefore, does not adequately treat withdrawal symptoms. Further research is needed to assess the safety and efficacy of higher dosages of NRT in pregnancy, specifically of combination treatment using dual forms of NRT. As NRT is safer than smoking, clinicians need to offer this option to all pregnant women who smoke. A practical guide for initiating and tailoring the dose of NRT in pregnancy is suggested.

Pharmaceutical strategies for smoking cessation during pregnancy

Introduction: Tobacco use is the most preventable cause of death worldwide, with over 7 million deaths per year. Smoking during pregnancy causes harm to the mother, fetus, and can result in problems for the infant from childhood into adulthood. Practitioners should ask all expectant mothers about tobacco use. For expectant mothers who smoke or recently quit, practitioners should advice to quit and provide psychosocial interventions. Rates of smoking during pregnancy differ between geographical locations, with estimates of 10.8% in the UK and 7.2% in the US. Practitioners should provide expectant mothers unable to quit smoking with information about the risks and benefits of pharmacotherapy and use a patient-centered approach to determine the use. Although there is no definitive evidence on birth outcomes, nicotine replacement therapy and bupropion are adequate pharmacotherapies to help those unable to quit. Areas covered: Herein, this author looks at the various pharmaceutical strategies to help patients cease smoking and provides expert perspectives on the subject. Expert opinion: Additional research on pharmacotherapy is warranted, especially with varenicline. Practitioners working with pregnant patients should be familiar with the evidence for pharmacotherapy in smoking cessation during pregnancy. This evidence can be difficult to navigate due to conflicting results and limitations with the trials.

Algorithm for resolving discrepancies between claims for smoking cessation pharmacotherapies during pregnancy and smoking status in delivery records: The impact on estimates of utilisation

BACKGROUND

The linkage of routine data collections are valuable for population-based evaluation of smoking cessation pharmacotherapy in pregnancy where little is known about the utilisation or safety of these pharmacotherapies antenatally. The use of routine data collections to study smoking cessation pharmacotherapy is limited by disparities among data sources. This study developed an algorithm to resolve disparity between the evidence of pharmacotherapy utilisation for smoking cessation and the recording of smoking in pregnancy, examined its face validity and assessed the implications on estimates of smoking cessation pharmacotherapy utilisation.

METHODS

Perinatal records (n = 1,098,203) of women who gave birth in the Australian States of Western Australia and New South Wales (2004-2012) were linked to hospital admissions and pharmaceutical dispensing data. An algorithm, based on dispensing information about the type of smoking therapy, timing and quantity of supply reclassified certain groups of women as smoking during pregnancy. Face validity of the algorithm was tested by examining the distribution of factors associated with inaccurate recording of smoking status among women that the algorithm classified as misreporting smoking in pregnancy. Rate of utilisation among smokers, according to original and reclassified smoking status, was measured, to demonstrate the utility of the algorithm.

RESULTS

Smoking cessation pharmacotherapy were dispensed to 2184 women during pregnancy, of those 1013 women were originally recorded as non-smoking as per perinatal and hospital data. Application of the algorithm reclassified 730 women as smoking during pregnancy. The algorithm satisfied the test of face validity-the expected demographic factors of marriage, private hospital delivery and higher socioeconomic status, were more common in women whom the algorithm identified as misreporting their smoking status. Application of the algorithm resulted in smoking cessation pharmacotherapy utilisation estimates ranging from 2.3-3.6% of all pregnancies.

CONCLUSION

Researchers can use the algorithm presented herein to improve the identification of smoking among women who use cessation pharmacotherapies during pregnancy. Improved identification can improve the validity of safety analyses of smoking cessation pharmacotherapy-providing clinicians with valuable evidence to use when counselling women on the role of pharmacotherapy for smoking cessation during pregnancy.

A systematic review of possible serious adverse health effects of nicotine replacement therapy

We conducted a systematic literature review to identify and critically evaluate studies of serious adverse health effects (SAHEs) in humans using nicotine replacement therapy (NRT) products. Serious adverse health effects refer to adverse events, leading to substantial disruption of the ability to conduct normal life functions. Strength of evidence evaluations and conclusions were also determined for the identified SAHEs. We evaluated 34 epidemiological studies and clinical trials, relating NRT use to cancer, reproduction/development, CVD, stroke and/or other SAHEs in patients, and four meta-analyses on effects in healthy populations. The overall evidence suffers from many limitations, the most significant being the short-term exposure (≤12 weeks) and follow-up to NRT product use in most of the studies, the common failure to account for changes in smoking behaviour following NRT use, and the sparse information on SAHEs by type of NRT product used. The only SAHE from NRT exposure we identified was an increase in respiratory congenital abnormalities reported in one study. Limited evidence indicated a lack of effect between NRT exposure and SAHEs for CVD and various reproduction/developmental endpoints. For cancer, stroke and other SAHEs, the evidence was inadequate to demonstrate any association with NRT use. Our conclusions agree with recent statements from authoritative bodies.

Prescribing of nicotine replacement therapy in and around pregnancy: a population-based study using primary care data

BACKGROUND

Licensing arrangements for nicotine replacement therapy (NRT) in the UK were broadened in 2005 to allow prescribing to pregnant smokers. However, estimates of NRT prescribing in pregnant females in the UK are currently lacking.

AIM

To assess trends in NRT prescribing around pregnancy, and variation in prescribing by maternal characteristics.

DESIGN AND SETTING

Population-based descriptive study using pregnancy data from The Health Improvement Network primary care database, 2001-2012.

METHOD

NRT prescriptions were identified during pregnancy and in the 9 months before and after. Annual prescribing prevalence was calculated. Logistic regression was used to assess females' likelihood of receiving prescriptions by maternal characteristics.

RESULTS

Of 388 142 pregnancies studied, NRT was prescribed in 7551 for an average duration of 2 weeks. The prescribing prevalence of NRT increased from 0.03% (0.7% in smokers) in 2001 to 2.6% (11.4% in smokers) in 2005, after which it remained stable. Prescribing prevalence of NRT before and after pregnancy was half the prevalence during pregnancy. The odds of prescribing NRT during pregnancy in smokers increased with socioeconomic deprivation (OR = 1.29, 95% CI = 1.15 to 1.45 in the most compared with the least deprived group). Prescribing was 33% higher in pregnant smokers with asthma (OR = 1.33, 95% CI = 1.22 to 1.45) and mental illness (OR = 1.33, 95% CI = 1.23 to 1.44) compared with smokers without these diagnoses.

CONCLUSION

NRT prescribing is higher during pregnancy compared with before and after, and is higher in smokers from more socioeconomically deprived groups, those with asthma or those diagnosed mental illness.

Respiratory disease in pregnancy

Many physiological and anatomical changes of pregnancy affect the respiratory system. These changes often affect the presentation and management of the various respiratory illnesses in pregnancy. This article focuses on several important respiratory issues in pregnancy. The management of asthma, one of the most common chronic illnesses in pregnancy, remains largely unchanged compared to the nonpregnant state. Infectious respiratory illness, including pneumonia and tuberculosis, are similarly managed in pregnancy with antibiotics, although special attention may be needed for antibiotic choices with more pregnancy safety data. When mechanical ventilation is necessary, consideration should be given to the maternal hemodynamics of pregnancy and fetal oxygenation. Maintaining maternal oxygen saturation above 95% is recommended to sustain optimal fetal oxygenation. Cigarette smoking has known risks in pregnancy, and current practice guidelines recommend offering cognitive and pharmacologic interventions to pregnant women to assist in smoking cessation.

Maternal cigarette smoking during pregnancy and reproductive health in children: a review of epidemiological studies

Maternal cigarette smoking may affect the intrauterine hormonal environment during pregnancy and this early fetal exposure may have detrimental effects on the future trajectory of reproductive health. In this review, we discuss the epidemiological literature on the association between prenatal exposure to maternal cigarette smoking and several aspects of reproductive health. The literature points towards an increased risk of the urogenital malformation cryptorchidism, but a potential protective effect on the risk of hypospadias in sons following prenatal cigarette smoking exposure. Studies on sexual maturation find a tendency towards accelerated pubertal development in exposed boys and girls. In adult life, prenatally exposed men have impaired semen quality compared with unexposed individuals, but an influence on fecundability, that is, the biological ability to reproduce, is less evident. We found no evidence to support an association between prenatal cigarette smoking exposure and testicular cancer. Among adult daughters, research is sparse and inconsistent, but exposure to cigarette smoking in utero may decrease fecundability. In conclusion, prenatal exposure to cigarette smoking may cause some long-term adverse effects on the reproductive health.

Effects of Occupational Tobacco Exposure on Foetal Growth, among Beedi Rollers in Coastal Karnataka

INTRODUCTION

Though there is ample evidence on adverse effects of tobacco exposure caused by smoking during pregnancy on foetal outcomes, there is lack of studies done on the effects of exposure caused by transdermal absorption, as is seen among beedi rolling women. Therefore, this study was planned, to assess the effect of maternal exposure to tobacco, in the form of beedi-rolling, on the birth weight and other neonatal anthropometric measurements.

MATERIALS AND METHODS

A cross sectional study with controls was conducted, with 102 beedi rollers forming the study group and an equal number of matched controls (control group) (total 204). Data was collected by using a pre-tested questionnaire and anthropometric examinations of the neonates were carried out within 48 hours of their births.

RESULTS

Mean birth weight of the newborns was 2.66 (SD=0.32) among those who were born to beedi rolling women and it was 2.63 (SD=0.38) kg among the control group. Crown heel length was 48.09 centimeters (SD=1.93) in the study group and it was 48.12 cm (SD=1.92) in the control group. Beedi rolling beyond the 7(th) month of gestation and for more than six hours per day was associated with a small but insignificant decline in birth weight and crown heel length.

CONCLUSION

Beedi-rolling was found to be relatively safe during pregnancy but it could produce adverse effects if it was continued into the third trimester and for longer durations. This study can make the beedi rollers as well as their employers aware of harmful over-exposure to beedi rolling and help them in preventing it.

The use of central nervous system active drugs during pregnancy

CNS-active drugs are used relatively often during pregnancy. Use during early pregnancy may increase the risk of a congenital malformation; use during the later part of pregnancy may be associated with preterm birth, intrauterine growth disturbances and neonatal morbidity. There is also a possibility that drug exposure can affect brain development with long-term neuropsychological harm as a result. This paper summarizes the literature on such drugs used during pregnancy: opioids, anticonvulsants, drugs used for Parkinson's disease, neuroleptics, sedatives and hypnotics, antidepressants, psychostimulants, and some other CNS-active drugs. In addition to an overview of the literature, data from the Swedish Medical Birth Register (1996-2011) are presented. The exposure data are either based on midwife interviews towards the end of the first trimester or on linkage with a prescribed drug register. An association between malformations and maternal use of anticonvulsants and notably valproic acid is well known from the literature and also demonstrated in the present study. Some other associations between drug exposure and outcome were found.

The Smoking MUMS (Maternal Use of Medications and Safety) Study: protocol for a population-based cohort study using linked administrative data

INTRODUCTION

Approximately 14% of Australian women smoke during pregnancy. Although the risk of adverse outcomes is reduced by smoking cessation, less than 35% of Australian women quit smoking spontaneously during pregnancy. Evidence for the efficacy of bupropion, varenicline or nicotine replacement therapy as smoking cessation aids in the non-pregnant population suggest that pharmacotherapy for smoking cessation is worth exploring in women of childbearing age. Currently, little is known about the utilisation, effectiveness and safety of pharmacotherapies for smoking cessation during pregnancy; neither the extent to which they are used prior to pregnancy nor whether their use has changed in response to related policy reforms. The Smoking MUMS (Maternal Use of Medications and Safety) Study will explore these issues using linked person-level data for a population-based cohort of Australian mothers.

METHODS AND ANALYSIS

The cohort will be assembled by linking administrative health records for all women who gave birth in New South Wales or Western Australia since 2003 and their children, including records relating to childbirth, use of pharmaceuticals, hospital admissions, emergency department presentations and deaths. These longitudinal linked data will be used to identify utilisation of smoking cessation pharmacotherapies during and between pregnancies and to explore the associated smoking cessation rates and maternal and child health outcomes. Subgroup and temporal analyses will identify potential differences between population groups including indigenous mothers and social security recipients and track changes associated with policy reforms that have made alternative smoking cessation pharmacotherapies available.

ETHICS AND DISSEMINATION

Ethical approval has been obtained for this study. To enhance the translation of the project's findings into policy and practice, policy and clinical stakeholders will be engaged through a reference group and a policy forum will be held. Outputs from the project will include scientific papers and summary reports designed for policy audiences.

Developmental hippocampal neuroplasticity in a model of nicotine replacement therapy during pregnancy and breastfeeding

RATIONALE

The influence of developmental nicotine exposure on the brain represents an important health topic in light of the popularity of nicotine replacement therapy (NRT) as a smoking cessation method during pregnancy.

OBJECTIVES

In this study, we used a model of NRT during pregnancy and breastfeeding to explore the consequences of chronic developmental nicotine exposure on cerebral neuroplasticity in the offspring. We focused on two dynamic lifelong phenomena in the dentate gyrus (DG) of the hippocampus that are highly sensitive to the environment: granule cell neurogenesis and long-term potentiation (LTP).

METHODS

Pregnant rats were implanted with osmotic mini-pumps delivering either nicotine or saline solutions. Plasma nicotine and metabolite levels were measured in dams and offspring. Corticosterone levels, DG neurogenesis (cell proliferation, survival and differentiation) and glutamatergic electrophysiological activity were measured in pups.

RESULTS

Juvenile (P15) and adolescent (P41) offspring exposed to nicotine throughout prenatal and postnatal development displayed no significant alteration in DG neurogenesis compared to control offspring. However, NRT-like nicotine exposure significantly increased LTP in the DG of juvenile offspring as measured in vitro from hippocampal slices, suggesting that the mechanisms underlying nicotine-induced LTP enhancement previously described in adult rats are already functional in pups.

CONCLUSIONS

These results indicate that synaptic plasticity is disrupted in offspring breastfed by dams passively exposed to nicotine in an NRT-like fashion.

Executive function profile in the offspring of women that smoked during pregnancy

INTRODUCTION

Smoking tobacco during pregnancy results in exposure to the fetal neuroteratogen nicotine. The current study evaluated if the offspring of smokers show abnormalities in maternal ratings of executive function, prevalence of Attention Deficit Hyperactivity Disorder (ADHD), and academic performance. A secondary objective was to determine the utility of online data collection.

METHODS

Mothers (N = 357) completed the parent form of the Behavioral Rating Inventory of Executive Function (BRIEF) and provided information about smoking during pregnancy.

RESULTS

The internal consistency of the BRIEF when administered electronically was quite satisfactory (Cronbach's α = .98). As anticipated, ADHD was more frequently diagnosed in the offspring of women that smoked at least 10 cigarettes/day (odds ratio [OR] = 2.64, 95% CI = 1.22-5.71). Higher (i.e., more problematic) ratings relative to unexposed children (p < .01) were only identified on the total BRIEF score, the Metacognition Index, and on the Initiate, Plan/Organize, and Monitor scales among children exposed to ≥10 cigarettes/day. Nicotine-exposed children were also more likely to perform less well than their classmates in math (OR = 2.78, 95% CI = 1.59-4.87) and reading (OR = 2.00, 95% CI = 1.10-3.63), and these academic effects were independent of maternal education levels.

CONCLUSIONS

This report provides preliminary evidence that the BRIEF has adequate psychometric properties when administered electronically and that mothers who smoke have offspring with lower executive function proficiency. These findings contribute to a larger literature that indicates that smoking during pregnancy results in adverse reproductive outcomes and, possibly, subtle but enduring deficits in prefrontal function.

The Danish National Birth Cohort: selected scientific contributions within perinatal epidemiology and future perspectives

INTRODUCTION

In this review a selection of studies published during the period 2002-2010, based on data from the Danish National Birth Cohort linked with other health registers, is described. Illustrative examples of studies addressing perinatal health outcomes (pregnancy complications and fetal and infant health) of a variety of exposures during pregnancy, as well as examples showing different methodological approaches in design and analyses of the studies, are presented.

RESEARCH TOPICS

The exposures of interest include alcohol drinking, coffee intake, smoking, use of nicotine substitutes, physical exercise, working conditions, medication and infections during pregnancy, and environmental possible toxins. The study designs cover straightforward cohort analyses, case-control studies and sub-cohort analyses with enriched data collection.

CONCLUSION

So far, the Danish National Birth Cohort has provided important knowledge for evidence-based antenatal care by giving more accurate risk estimates for adverse pregnancy outcomes associated with the exposures of interest. Some new potential hazardous exposures during pregnancy have been identified and others have been put to rest. We believe that this investment in epidemiologic infrastructure was well spent. The existence of the Danish National Birth Cohort together with other cohorts and national registers has given Denmark a leading position in reproductive epidemiology.

Racial and ethnic disparities in United States: stillbirth rates: trends, risk factors, and research needs

As with most adverse health outcomes, there has been long standing and persistent racial and ethnic disparity for stillbirth in the United States. In 2005, the stillbirth rate (fetal deaths ≥ 20 weeks' gestation per 1000 fetal deaths and live births) for non-Hispanic blacks was 11.13 compared with 4.79 for non-Hispanic whites. Rates were intermediate for American Indian or Alaska Natives (6.17) and Hispanics (5.44). There is racial disparity for both early (< 28 weeks' gestation) and late stillbirths. We review available data regarding risk factors for stillbirth with a focus on those factors that are more prevalent in certain racial/ethnic groups and those factors that appear to have a more profound effect in certain racial/ethnic groups. Although many factors, including genetics, environment, stress, social issues, access to and quality of medical care and behavior, contribute to racial disparity in stillbirth, the reasons for the disparity remain unclear. Knowledge gaps and recommendations for further research and interventions intended to reduce racial disparity in stillbirth are highlighted.

Controversy and evidence about nicotine replacement therapy in pregnancy

Nicotine replacement therapy (NRT) is effective for smoking cessation, but much controversy surrounds its use during pregnancy. The importance of finding ways to help pregnant smokers quit is undisputed, since smoking during pregnancy causes harm to the mother and the fetus, with effects of smoke exposure extending into childhood. Researchers and providers are divided, however, with respect to opinions of safety and efficacy of NRT use in pregnant smokers. The research-based evidence on the topic is limited, but there are studies examining the efficacy of NRT in pregnancy. This article presents the evidence for this smoking cessation methodology in pregnancy.

Long-term consequences of fetal and neonatal nicotine exposure: a critical review

Cigarette smoking during pregnancy is associated with numerous obstetrical, fetal, and developmental complications, as well as an increased risk of adverse health consequences in the adult offspring. Nicotine replacement therapy (NRT) has been developed as a pharmacotherapy for smoking cessation and is considered to be a safer alternative for women to smoking during pregnancy. The safety of NRT use during pregnancy has been evaluated in a limited number of short-term human trials, but there is currently no information on the long-term effects of developmental nicotine exposure in humans. However, animal studies suggest that nicotine alone may be a key chemical responsible for many of the long-term effects associated with maternal cigarette smoking on the offspring, such as impaired fertility, type 2 diabetes, obesity, hypertension, neurobehavioral defects, and respiratory dysfunction. This review will examine the long-term effects of fetal and neonatal nicotine exposure on postnatal health.

What do we know about the role of pharmacotherapy for smoking cessation before or during pregnancy?

SIGNIFICANCE

Given the substantial health risks of smoking during pregnancy, and the potential of pharmacotherapy to enhance quit rates, a need exists to examine the utility of pharmacotherapy for smoking cessation during pregnancy.

LITERATURE REVIEW

We briefly review the first-line medications that are recommended for smoking cessation in nonpregnant adults. Additionally, we review the toxicity of tobacco smoke and the potential risks of pharmacotherapy as evidenced by animal studies. We review in more detail studies conducted in pregnant women, including (a) observational studies, (b) short-term safety and longer term uncontrolled studies, and (c) randomized controlled clinical trials (both effectiveness and efficacy studies).

DISCUSSION

Because the safety and efficacy of pharmacotherapy for smoking cessation during pregnancy have not been established, no definitive recommendations can be made on the topic. Effectiveness trials have shown that nicotine replacement therapy (NRT) enhances smoking cessation during pregnancy, but efficacy trials have not shown an advantage for NRT compared with placebo treatment. Small sample size or poor medication compliance (with either the dose or the duration of treatment) may contribute to lack of efficacy in placebo-controlled NRT trials. However, these trials showed that NRT did not adversely affect birth outcomes and increased birth weight. Based on these findings and the fact that all medications have some risk, psychosocial interventions should be the first treatment option for pregnant smokers. Additional research is needed to determine fully the risks and benefits of the various pharmacotherapies for smoking cessation during pregnancy.

Reducing stillbirths: behavioural and nutritional interventions before and during pregnancy

BACKGROUND

The vast majority of global stillbirths occur in low- and middle-income countries, and in many settings, the majority of stillbirths occur antenatally, prior to the onset of labour. Poor nutritional status, lack of antenatal care and a number of behaviours increase women's risk of stillbirth in many resource-poor settings. Interventions to reduce these risks could reduce the resulting burden of stillbirths, but the evidence for the impact of such interventions has not yet been comprehensively evaluated.

METHODS

This second paper of a systematic review of interventions that could plausibly impact stillbirth rates covers 12 different interventions relating to behavioural and socially mediated risk factors, including exposures to harmful practices and substances, antenatal care utilisation and quality, and maternal nutrition before and during pregnancy. The search strategy reviewed indexed medical journals on PubMed and the Cochrane Library. If any eligible randomised controlled trials were identified that were published after the most recent Cochrane review, they were added to generate new meta-analyses. Interventions covered in this paper have a focus on low- and middle-income countries, both because of the large burden of stillbirths and because of the high prevalence of risk factors including maternal malnutrition and harmful environmental exposures. The reviews and studies belonging to these interventions were graded and conclusions derived about the evidence of benefit of these interventions.

RESULTS

From a programmatic perspective, none of the interventions achieved clear evidence of benefit. Evidence for some socially mediated risk factors were identified, such as exposure to indoor air pollution and birth spacing, but still require the development of appropriate interventions. There is a need for additional studies on culturally appropriate behavioural interventions and clinical trials to increase smoking cessation and reduce exposure to smokeless tobacco. Balanced protein-energy supplementation was associated with reduced stillbirth rates, but larger well-designed trials are required to confirm findings. Peri-conceptional folic acid supplementation significantly reduces neural tube defects, yet no significant associated reductions in stillbirth rates have been documented. Evidence for other nutritional interventions including multiple micronutrient and Vitamin A supplementation is weak, suggesting the need for further research to assess potential of nutritional interventions to reduce stillbirths.

CONCLUSION

Antenatal care is widely used in low- and middle-income countries, and provides a natural facility-based contact through which to provide or educate about many of the interventions we reviewed. The impact of broader socially mediated behaviors, such as fertility decision-making, access to antenatal care, and maternal diet and exposures like tobacco and indoor air pollution during pregnancy, are poorly understood, and further research and appropriate interventions are needed to test the association of these behaviours with stillbirth outcomes. For most nutritional interventions, larger randomised controlled trials are needed which report stillbirths disaggregated from composite perinatal mortality. Many antepartum stillbirths are potentially preventable in low- and middle-income countries, particularly through dietary and environmental improvement, and through improving the quality of antenatal care - particularly including diagnosis and management of high-risk pregnancies - that pregnant women receive.