title: Effects of ambient levels of air pollution generated by traffic on birth and placental weights in mice.
abstract: OBJECTIVE
  To examine whether there is an association between fetal and/or placental weight and exposure to ambient levels of air pollution in mice.
  
  
  METHODS
  Chronic experiments on mice that were exposed to polluted vs. clean air.
  
  
  METHODS
  Environmental exposure to atmospheric pollution.
  
  
  METHODS
  Female Swiss mice (n = 70) were maintained at different stages of gestation in an exposure chamber located at an intersection with heavy traffic in a major city in Brazil. Control mice were maintained in a similar chamber, located adjacent to the exposure chamber but equipped with filters for particles and reactive gases.
  
  
  METHODS
  Animals were divided into six groups as follows: no exposure, exposure to a polluted chamber throughout gestation, exposure to a polluted chamber during the 1st week of pregnancy, exposure to a polluted chamber during the 2nd and 3rd weeks, exposure to a polluted chamber during the 1st and 2nd week, and exposure to a polluted chamber during the 3rd week.
  
  
  METHODS
  At the end of the gestational period, the determination of fetal and placental weight was performed after cesarean section.
  
  
  RESULTS
  Exposure to air pollution during the 1st week of pregnancy promoted a significant reduction in fetal weight. Mice exposed to polluted air, in any phase of gestation, presented with lower placental weight in comparison to mice maintained in clean chambers.
  
  
  CONCLUSIONS
  Exposure to ambient levels of traffic pollution at early phases of gestation is a determinant for decreased final fetal weight. Placental weight is reduced with exposure to air pollution at any phase of gestation.
authors.affiliation: Department of Pathology, Laboratory of Air Pollution, University of São Paulo, São Paulo, Brazil. rors@terra.com.br
authors.forename: Ingrid Ramos
authors.initials: IR
authors.lastname: Rocha E Silva
authors.forename: Ana Julia F C
authors.initials: AJ
authors.lastname: Lichtenfels
authors.forename: Luis Alberto
authors.initials: LA
authors.lastname: Amador Pereira
authors.forename: Paulo H N
authors.initials: PH
authors.lastname: Saldiva
mesh_terms: D000393:Air Pollutants / Q000633:toxicity*; D000818:Animals; D000831:Animals, Newborn; D001273:Atmosphere Exposure Chambers; D001724:Birth Weight / Q000187:drug effects*; D002585:Cesarean Section; D005260:Female; D020567:Fetal Weight / Q000187:drug effects*; D005865:Gestational Age; D018811:Maternal Exposure; D051379:Mice; D009929:Organ Size; D010920:Placenta / Q000187:drug effects*; D010929:Placentation; D001335:Vehicle Emissions / Q000633:toxicity*
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions