title: Residential exposure to outdoor air pollution during pregnancy and anthropometric measures at birth in a multicenter cohort in Spain.
abstract: BACKGROUND
  A growing body of research suggests that prenatal exposure to air pollution may be harmful to fetal development. We assessed the association between exposure to air pollution during pregnancy and anthropometric measures at birth in four areas within the Spanish Children's Health and Environment (INMA) mother and child cohort study.
  
  
  METHODS
  Exposure to ambient nitrogen dioxide (NO2) and benzene was estimated for the residence of each woman (n = 2,337) for each trimester and for the entire pregnancy. Outcomes included birth weight, length, and head circumference. The association between residential outdoor air pollution exposure and birth outcomes was assessed with linear regression models controlled for potential confounders. We also performed sensitivity analyses for the subset of women who spent more time at home during pregnancy. Finally, we performed a combined analysis with meta-analysis techniques.
  
  
  RESULTS
  In the combined analysis, an increase of 10 µg/m3 in NO2 exposure during pregnancy was associated with a decrease in birth length of -0.9 mm [95% confidence interval (CI), -1.8 to -0.1 mm]. For the subset of women who spent ≥ 15 hr/day at home, the association was stronger (-0.16 mm; 95% CI, -0.27 to -0.04). For this same subset of women, a reduction of 22 g in birth weight was associated with each 10-µg/m3 increase in NO2 exposure in the second trimester (95% CI, -45.3 to 1.9). We observed no significant relationship between benzene levels and birth outcomes.
  
  
  CONCLUSIONS
  NO2 exposure was associated with reductions in both length and weight at birth. This association was clearer for the subset of women who spent more time at home.
authors.affiliation: Consortium for Research on Epidemiology and Public Health (CIBERESP), Spain. estarlich_mar@gva.es
authors.forename: Marisa
authors.initials: M
authors.lastname: Estarlich
authors.forename: Ferran
authors.initials: F
authors.lastname: Ballester
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Aguilera
authors.forename: Ana
authors.initials: A
authors.lastname: Fernández-Somoano
authors.forename: Aitana
authors.initials: A
authors.lastname: Lertxundi
authors.forename: Sabrina
authors.initials: S
authors.lastname: Llop
authors.forename: Carmen
authors.initials: C
authors.lastname: Freire
authors.forename: Adonina
authors.initials: A
authors.lastname: Tardón
authors.forename: Mikel
authors.initials: M
authors.lastname: Basterrechea
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
authors.forename: Carmen
authors.initials: C
authors.lastname: Iñiguez
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D001554:Benzene / Q000032:analysis / Q000633:toxicity; D001724:Birth Weight / Q000187:drug effects; D049628:Body Size / Q000187:drug effects; D015331:Cohort Studies; D004784:Environmental Monitoring; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D019570:Inhalation Exposure / Q000009:adverse effects / Q000032:analysis* / Q000706:statistics & numerical data; D018811:Maternal Exposure / Q000009:adverse effects* / Q000706:statistics & numerical data; D009585:Nitrogen Dioxide / Q000032:analysis / Q000633:toxicity; D011247:Pregnancy; D011446:Prospective Studies; D012111:Residence Characteristics; D013030:Spain; D011795:Surveys and Questionnaires; D001335:Vehicle Emissions / Q000032:analysis / Q000633:toxicity; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D001335:Vehicle Emissions; D001554:Benzene; D009585:Nitrogen Dioxide