title: Exposure to disinfection by-products, fetal growth, and prematurity: a systematic review and meta-analysis.
abstract: BACKGROUND
  Exposure to total trihalomethanes in drinking water has been associated with several adverse birth outcomes relating to fetal growth and prematurity.
  
  
  METHODS
  We carried out a systematic review and meta-analysis of epidemiologic studies featuring original peer-reviewed data on the association of total trihalomethane exposure and health outcomes related to fetal growth and prematurity.
  
  
  RESULTS
  A comprehensive literature search yielded 37 studies, 15 of which were selected for the extraction of relative risks relating adverse birth outcomes to trihalomethane exposure. Sufficient data were available for meta-analyses to be carried out for 4 adverse birth outcomes: low birth weight (LBW), term low birth weight (term LBW), preterm delivery, and small for gestational age (SGA) (including intra uterine growth retardation). We found little or no evidence for associations between third trimester trihalomethane exposure and LBW (odds ratio per 10 microg total trihalomethane/L = 1.00 [95% confidence interval = 0.97-1.03]), term LBW (1.03 [0.93-1.15]), or preterm delivery (0.99 [0.98-1.00]), but some evidence for SGA (1.01 [1.00-1.02]).
  
  
  CONCLUSIONS
  There was little or no evidence for associations between total trihalomethane concentration and adverse birth outcomes relating to fetal growth and prematurity, with the possible exception of SGA. We discuss these findings and the uncertainties-relating particularly to exposure-that may have affected them.
authors.affiliation: Department of Epidemiology and Public Health, Imperial College London, London, United Kingdom. j.grellier@imperial.ac.uk
authors.forename: James
authors.initials: J
authors.lastname: Grellier
authors.forename: James
authors.initials: J
authors.lastname: Bennett
authors.forename: Evridiki
authors.initials: E
authors.lastname: Patelarou
authors.forename: Rachel B
authors.initials: RB
authors.lastname: Smith
authors.forename: Mireille B
authors.initials: MB
authors.lastname: Toledano
authors.forename: Lesley
authors.initials: L
authors.lastname: Rushton
authors.forename: David J
authors.initials: DJ
authors.lastname: Briggs
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Nieuwenhuijsen
mesh_terms: D004202:Disinfectants / Q000633:toxicity*; D005260:Female; D047109:Fetal Development / Q000187:drug effects*; D006801:Humans; D011247:Pregnancy; D011256:Pregnancy Outcome; D047928:Premature Birth / Q000139:chemically induced*; D022882:Trihalomethanes / Q000302:isolation & purification / Q000633:toxicity*; D014873:Water Pollutants / Q000633:toxicity*; D014881:Water Supply
chemical_list: D004202:Disinfectants; D022882:Trihalomethanes; D014873:Water Pollutants