title: A systematic review of maternal smoking during pregnancy and fetal measurements with meta-analysis.
abstract: BACKGROUND
  Maternal smoking during pregnancy is linked to reduced birth weight but the gestation at onset of this relationship is not certain. We present a systematic review of the literature describing associations between maternal smoking during pregnancy and ultrasound measurements of fetal size, together with an accompanying meta-analysis.
  
  
  METHODS
  Studies were selected from electronic databases (OVID, EMBASE and Google Scholar) that examined associations between maternal smoking or smoke exposure and antenatal fetal ultrasound measurements. Outcome measures were first, second or third trimester fetal measurements.
  
  
  RESULTS
  There were 284 abstracts identified, 16 papers were included in the review and the meta-analysis included data from eight populations. Maternal smoking was associated with reduced second trimester head size (mean reduction 0.09 standard deviation (SD) [95% CI 0.01, 0.16]) and femur length (0.06 [0.01, 0.10]) and reduced third trimester head size (0.18 SD [0.13, 0.23]), femur length (0.27 SD [0.21, 0.32]) and estimated fetal weight (0.18 SD [0.11, 0.24]). Higher maternal cigarette consumption was associated with a lower z score for head size in the second (mean difference 0.09 SD [0, 0.19]) and third (0.15 SD [0.03, 0.26]) trimesters compared to lower consumption. Fetal measurements were not reduced for those whose mothers quit before or after becoming pregnant compared to mothers who had never smoked.
  
  
  CONCLUSIONS
  Maternal smoking during pregnancy is associated with reduced fetal measurements after the first trimester, particularly reduced head size and femur length. These effects may be attenuated if mothers quit or reduce cigarette consumption during pregnancy.
authors.affiliation: Child Health, University of Aberdeen, Aberdeen, United Kingdom.
authors.forename: Miriam
authors.initials: M
authors.lastname: Abraham
authors.affiliation: Child Health, University of Aberdeen, Aberdeen, United Kingdom.
authors.forename: Salem
authors.initials: S
authors.lastname: Alramadhan
authors.affiliation: FISABIO - Universitat Jaume I - Universitat de València Epidemiology and Environmental Health Joint Research Unit and Spanish Consortium for Research on Epidemiology and Public Health (CIBERESP), Valencia, Spain.
authors.forename: Carmen
authors.initials: C
authors.lastname: Iniguez
authors.affiliation: The Generation R Study, Department of Paediatrics, Department of Epidemiology, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, The Netherlands.
authors.forename: Liesbeth
authors.initials: L
authors.lastname: Duijts
authors.affiliation: The Generation R Study, Department of Paediatrics, Department of Epidemiology, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, The Netherlands.
authors.forename: Vincent W V
authors.initials: VW
authors.lastname: Jaddoe
authors.affiliation: The Generation R Study, Department of Paediatrics, Department of Epidemiology, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, The Netherlands.
authors.forename: Herman T
authors.initials: HT
authors.lastname: Den Dekker
authors.affiliation: MRC Lifecourse Epidemiology Unit and NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.
authors.forename: Sarah
authors.initials: S
authors.lastname: Crozier
authors.affiliation: MRC Lifecourse Epidemiology Unit and NIHR Southampton Biomedical Research Centre, University of Southampton and University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.
authors.forename: Keith M
authors.initials: KM
authors.lastname: Godfrey
authors.affiliation: University College London, London, United Kingdom.
authors.forename: Peter
authors.initials: P
authors.lastname: Hindmarsh
authors.affiliation: Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Torstein
authors.initials: T
authors.lastname: Vik
authors.affiliation: Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: Geir W
authors.initials: GW
authors.lastname: Jacobsen
authors.affiliation: Department of Environmental Epidemiology, Nofer Institute of Occupational Medicine, Lodz, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Hanke
authors.affiliation: Department of Environmental Epidemiology, Nofer Institute of Occupational Medicine, Lodz, Poland.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Sobala
authors.affiliation: Child Health, University of Aberdeen, Aberdeen, United Kingdom.
authors.forename: Graham
authors.initials: G
authors.lastname: Devereux
authors.affiliation: Child Health, University of Aberdeen, Aberdeen, United Kingdom.
authors.forename: Steve
authors.identifier: http://orcid.org/0000-0001-8393-5060
authors.initials: S
authors.lastname: Turner
mesh_terms: D001724:Birth Weight; D005260:Female; D047109:Fetal Development; D005317:Fetal Growth Retardation / Q000209:etiology*; D006257:Head / Q000196:embryology; D006801:Humans; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011262:Pregnancy Trimester, Second; D011263:Pregnancy Trimester, Third; D012907:Smoking / Q000009:adverse effects*; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
chemical_list: D014028:Tobacco Smoke Pollution