Abstract :
Keywords Nicotine replacement therapy; E-cigarettes; Lung; Development; Lung function Highlights * NRT and e-cigarettes are offered to pregnant women wishing to stop smoking. * Gestational nicotine exposure alters development of the fetal lung. * Altered lung development results in abnormal newborn and infant respiratory function. * No trials consider the effect of NRT & e-cigarettes on infant respiratory outcomes. Abstract Background Nicotine replacement therapy (NRT) and e-cigarettes are recommended to pregnant women who wish to stop smoking. Albeit eliminating other harmful components of cigarettes, those alternatives still expose the developing fetus to nicotine. The lungs may be particularly vulnerable to damage by nicotine as there is widespread nicotinic-acetylcholine receptor expression in the lungs. There is, however, a paucity of information about the effect of NRT and e-cigarette use in pregnancy on infant respiratory outcomes. Aims To explore the effect of NRT and e-cigarettes on the developing lung. Study design A literature search was undertaken to examine the use and safety of nicotine-replacement strategies in pregnancy, with a focus on infant respiratory outcomes. This included experimental studies investigating the effect of isolated "gestational" nicotine on the developing lung. Outcome measures Respiratory outcomes in animal studies and infants. Results Animal studies investigating the effect of gestational nicotine exposure on fetal lung development demonstrated abnormal lung growth; including abnormal airway branching and alveolar development. Consequently, offspring display altered pulmonary mechanics, including both increased respiratory rate and airway resistance. These findings mirror respiratory pathology observed in infants born to smoking mothers. Human trials of NRT and e-cigarette use in pregnancy have not identified adverse perinatal outcomes regarding reduced birthweight or prematurity, but have not considered infant and childhood respiratory outcomes. Conclusions Nicotine can impair fetal lung development, leading to concerns regarding the safety of NRT and e-cigarettes in pregnancy. Studies have yet to explore the impact of these nicotine-containing products on infant respiratory outcomes. Abbreviations NRT, Nicotine Replacement Therapy Author Affiliation: (a) Department of Women and Children's Health, School of Life Course Sciences, Faculty of Life Sciences and Medicine, King's College London, SE5 9RS, United Kingdom (b) Neonatal Intensive Care Centre, King's College Hospital NHS Foundation Trust, London, SE5 9RS, United Kingdom (c) Asthma UK Centre for Allergic Mechanisms in Asthma, King's College London, SE1 9RT, United Kingdom (d) National Institute for Health Research (NIHR) Biomedical Research Centre based at Guy's and St Thomas' NHS Foundation Trust and King's College London, SE1 9RT, United Kingdom * Corresponding author at: Neonatal Intensive Care Centre, 4th Floor Golden Jubilee Wing, King's College Hospital, Denmark Hill, London SE5 9RS, United Kingdom. Article History: Received 23 June 2021; Revised 10 November 2021; Accepted 16 November 2021 (footnote)[white star] Funding sources: EEW was supported by the Charles Wolfson Charitable Trust and additionally by SLE. The research was supported by the National Institute for Health Research (NIHR) Biomedical Research Centre based at Guy's and St Thomas' NHS Foundation Trust and King's College London. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. Byline: Nadja Bednarczuk (a), Emma E. Williams (a), Theodore Dassios (a,b), Anne Greenough [anne.greenough@kcl.ac.uk] (a,c,d,*)