title: Parental smoking during pregnancy and its association with low birth weight, small for gestational age, and preterm birth offspring: a birth cohort study.
abstract: BACKGROUND
  Intrauterine exposure to tobacco smoke has been discerned as an important risk factor for low birth weight (LBW), small for gestational age (SGA), and preterm birth infants. In this cohort study, we investigated the association of the amount of parental smoking during the different pregnancy stages with birth weight and the incidence of preterm delivery.
  
  
  METHODS
  Our study population was acquired from the Taiwan Birth Cohort Study. Between June 2005 and July 2006, 21,248 postpartum women were interviewed 6 months after their deliveries by a structured questionnaire. The parents were divided into four groups according to the amount of smoking during preconception, the first trimester, and the second and third trimesters. The relationships of parental smoking with gestational age and birth weight during the different pregnancy stages were assessed using multivariate linear regression. Multiple logistic regression analyses were performed to estimate the odds ratios and 95% confidence intervals of preterm delivery, LBW, and SGA infants during the different parental smoking status and the different pregnancy stages.
  
  
  RESULTS
  After adjusting for the physical and socioeconomic status of the parents and for paternal smoking during the same period, we found that maternal smoking decreased birth weight. Compared with the nonsmoking groups, all the maternal smoking groups had higher incidences of LBW, SGA, and preterm birth infants, especially when the mothers smoked >20 cigarettes/day. The association of paternal smoking with LBW, SGA, and preterm birth infants was insignificant.
  
  
  CONCLUSIONS
  Maternal smoking is responsible for increased incidences of LBW and preterm delivery of babies, and therefore, smoking cessation/reduction should be advised to pregnant women to reduce morbidities in their neonates. Further studies are needed to clarify the correlation of fetal health with passive smoking, including exposure to environmental tobacco smoke and to other smokers in the family.
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital and National Taiwan University, College of Medicine, Taipei, Taiwan; Department of Pediatrics, Far Eastern Memorial Hospital, Panchiao, Taiwan.
authors.forename: Ting-Jung
authors.initials: TJ
authors.lastname: Ko
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital and National Taiwan University, College of Medicine, Taipei, Taiwan; Department of Pediatrics, Shin Kong Wu Ho-Su Memorial Hospital, Taipei, Taiwan.
authors.forename: Li-Yi
authors.initials: LY
authors.lastname: Tsai
authors.affiliation: Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University, College of Public Health, Taipei, Taiwan.
authors.forename: Li-Ching
authors.initials: LC
authors.lastname: Chu
authors.affiliation: Department of Pediatrics, Far Eastern Memorial Hospital, Panchiao, Taiwan.
authors.forename: Shu-Jen
authors.initials: SJ
authors.lastname: Yeh
authors.affiliation: Department of Pediatrics, Far Eastern Memorial Hospital, Panchiao, Taiwan.
authors.forename: Cheung
authors.initials: C
authors.lastname: Leung
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital and National Taiwan University, College of Medicine, Taipei, Taiwan.
authors.forename: Chien-Yi
authors.initials: CY
authors.lastname: Chen
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital and National Taiwan University, College of Medicine, Taipei, Taiwan.
authors.forename: Hung-Chieh
authors.initials: HC
authors.lastname: Chou
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital and National Taiwan University, College of Medicine, Taipei, Taiwan.
authors.forename: Po-Nien
authors.initials: PN
authors.lastname: Tsao
authors.affiliation: Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University, College of Public Health, Taipei, Taiwan; Department of Public Health, National Taiwan University, College of Public Health, Taipei, Taiwan; Department of Environmental and Occupational Medicine, National Taiwan University Hospital and National Taiwan University, College of Medicine, Taipei, Taiwan.
authors.forename: Pau-Chung
authors.initials: PC
authors.lastname: Chen
authors.affiliation: Department of Pediatrics, National Taiwan University Hospital and National Taiwan University, College of Medicine, Taipei, Taiwan. Electronic address: hsiehws@ntu.edu.tw.
authors.forename: Wu-Shiun
authors.initials: WS
authors.lastname: Hsieh
mesh_terms: D015331:Cohort Studies; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight; D007236:Infant, Small for Gestational Age; D010290:Parents; D011247:Pregnancy; D047928:Premature Birth / Q000209:etiology*; D012907:Smoking / Q000009:adverse effects*
keywords: birth cohort; low birth weight; preterm; smoking