title: Exposure to trihalomethanes through different water uses and birth weight, small for gestational age, and preterm delivery in Spain.
abstract: BACKGROUND
  Evidence associating exposure to water disinfection by-products with reduced birth weight and altered duration of gestation remains inconclusive.
  
  
  OBJECTIVE
  We assessed exposure to trihalomethanes (THMs) during pregnancy through different water uses and evaluated the association with birth weight, small for gestational age (SGA), low birth weight (LBW), and preterm delivery.
  
  
  METHODS
  Mother-child cohorts set up in five Spanish areas during the years 2000-2008 contributed data on water ingestion, showering, bathing, and swimming in pools. We ascertained residential THM levels during pregnancy periods through ad hoc sampling campaigns (828 measurements) and regulatory data (264 measurements), which were modeled and combined with personal water use and uptake factors to estimate personal uptake. We defined outcomes following standard definitions and included 2,158 newborns in the analysis.
  
  
  RESULTS
  Median residential THM ranged from 5.9 μg/L (Valencia) to 114.7 μg/L (Sabadell), and speciation differed across areas. We estimated that 89% of residential chloroform and 96% of brominated THM uptakes were from showering/bathing. The estimated change of birth weight for a 10% increase in residential uptake was -0.45 g (95% confidence interval: -1.36, 0.45 g) for chloroform and 0.16 g (-1.38, 1.70 g) for brominated THMs. Overall, THMs were not associated with SGA, LBW, or preterm delivery.
  
  
  CONCLUSIONS
  Despite the high THM levels in some areas and the extensive exposure assessment, results suggest that residential THM exposure during pregnancy driven by inhalation and dermal contact routes is not associated with birth weight, SGA, LBW, or preterm delivery in Spain.
authors.affiliation: Centre for Research in Environmental Epidemiology (CREAL), Barcelona, Spain. cvillanueva@creal.cat
authors.forename: Cristina M
authors.initials: CM
authors.lastname: Villanueva
authors.forename: Esther
authors.initials: E
authors.lastname: Gracia-Lavedán
authors.forename: Jesús
authors.initials: J
authors.lastname: Ibarluzea
authors.forename: Loreto
authors.initials: L
authors.lastname: Santa Marina
authors.forename: Ferran
authors.initials: F
authors.lastname: Ballester
authors.forename: Sabrina
authors.initials: S
authors.lastname: Llop
authors.forename: Adonina
authors.initials: A
authors.lastname: Tardón
authors.forename: Mariana F
authors.initials: MF
authors.lastname: Fernández
authors.forename: Carmen
authors.initials: C
authors.lastname: Freire
authors.forename: Fernando
authors.initials: F
authors.lastname: Goñi
authors.forename: Xavier
authors.initials: X
authors.lastname: Basagaña
authors.forename: Manolis
authors.initials: M
authors.lastname: Kogevinas
authors.forename: Joan O
authors.initials: JO
authors.lastname: Grimalt
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
mesh_terms: D000328:Adult; D015331:Cohort Studies; D004781:Environmental Exposure / Q000032:analysis*; D005260:Female; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D016015:Logistic Models; D008962:Models, Theoretical; D011247:Pregnancy; D047928:Premature Birth / Q000453:epidemiology*; D013030:Spain / Q000453:epidemiology; D022882:Trihalomethanes / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D022882:Trihalomethanes; D014874:Water Pollutants, Chemical