title: Maternal arsenic exposure, arsenic methylation efficiency, and birth outcomes in the Biomarkers of Exposure to ARsenic (BEAR) pregnancy cohort in Mexico.
abstract: BACKGROUND
  Exposure to inorganic arsenic (iAs) from drinking water is a global public health problem, yet much remains unknown about the extent of exposure in susceptible populations.
  
  
  OBJECTIVE
  We aimed to establish the Biomarkers of Exposure to ARsenic (BEAR) prospective pregnancy cohort in Gómez Palacio, Mexico, to better understand the effects of iAs exposure on pregnant women and their children.
  
  
  METHODS
  Two hundred pregnant women were recruited for this study. Concentrations of iAs in drinking water (DW-iAs) and maternal urinary concentrations of iAs and its monomethylated and dimethylated metabolites (MMAs and DMAs, respectively) were determined. Birth outcomes were analyzed for their relationship to DW-iAs and to the concentrations and proportions of maternal urinary arsenicals.
  
  
  RESULTS
  DW-iAs for the study subjects ranged from < 0.5 to 236 μg As/L. More than half of the women (53%) had DW-iAs that exceeded the World Health Organization's recommended guideline of 10 μg As/L. DW-iAs was significantly associated with the sum of the urinary arsenicals (U-tAs). Maternal urinary concentrations of MMAs were negatively associated with newborn birth weight and gestational age. Maternal urinary concentrations of iAs were associated with lower mean gestational age and newborn length.
  
  
  CONCLUSIONS
  Biomonitoring results demonstrate that pregnant women in Gómez Palacio are exposed to potentially harmful levels of DW-iAs. The data support a relationship between iAs metabolism in pregnant women and adverse birth outcomes. The results underscore the risks associated with iAs exposure in vulnerable populations.
authors.affiliation: Department of Epidemiology, and Department of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill, Gillings School of Public Heath, Chapel Hill, North Carolina, USA.
authors.forename: Jessica E
authors.initials: JE
authors.lastname: Laine
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Bailey
authors.forename: Marisela
authors.initials: M
authors.lastname: Rubio-Andrade
authors.forename: Andrew F
authors.initials: AF
authors.lastname: Olshan
authors.forename: Lisa
authors.initials: L
authors.lastname: Smeester
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Drobná
authors.forename: Amy H
authors.initials: AH
authors.lastname: Herring
authors.forename: Miroslav
authors.initials: M
authors.lastname: Stýblo
authors.forename: Gonzalo G
authors.initials: GG
authors.lastname: García-Vargas
authors.forename: Rebecca C
authors.initials: RC
authors.lastname: Fry
mesh_terms: D000328:Adult; D001151:Arsenic / Q000378:metabolism / Q000633:toxicity* / Q000652:urine; D015415:Biomarkers / Q000378:metabolism; D049628:Body Size; D060766:Drinking Water / Q000737:chemistry; D004785:Environmental Pollutants / Q000378:metabolism / Q000633:toxicity*; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D018811:Maternal Exposure / Q000706:statistics & numerical data*; D008800:Mexico; D011247:Pregnancy; D011446:Prospective Studies
chemical_list: D015415:Biomarkers; D060766:Drinking Water; D004785:Environmental Pollutants; D001151:Arsenic