title: Prenatal exposure to traffic-related air pollution and ultrasound measures of fetal growth in the INMA Sabadell cohort.
abstract: BACKGROUND
  Few studies have used longitudinal ultrasound measurements to assess the effect of traffic-related air pollution on fetal growth.
  
  
  OBJECTIVE
  We examined the relationship between exposure to nitrogen dioxide (NO2) and aromatic hydrocarbons [benzene, toluene, ethylbenzene, m/p-xylene, and o-xylene (BTEX)] on fetal growth assessed by 1,692 ultrasound measurements among 562 pregnant women from the Sabadell cohort of the Spanish INMA (Environment and Childhood) study.
  
  
  METHODS
  We used temporally adjusted land-use regression models to estimate exposures to NO2 and BTEX. We fitted mixed-effects models to estimate longitudinal growth curves for femur length (FL), head circumference (HC), abdominal circumference (AC), biparietal diameter (BPD), and estimated fetal weight (EFW). Unconditional and conditional SD scores were calculated at 12, 20, and 32 weeks of gestation. Sensitivity analyses were performed considering time-activity patterns during pregnancy.
  
  
  RESULTS
  Exposure to BTEX from early pregnancy was negatively associated with growth in BPD during weeks 20-32. None of the other fetal growth parameters were associated with exposure to air pollution during pregnancy. When considering only women who spent < 2 hr/day in nonresidential outdoor locations, effect estimates were stronger and statistically significant for the association between NO2 and growth in HC during weeks 12-20 and growth in AC, BPD, and EFW during weeks 20-32.
  
  
  CONCLUSIONS
  Our results lend some support to an effect of exposure to traffic-related air pollutants from early pregnancy on fetal growth during mid-pregnancy..
authors.affiliation: Centre for Research in Environmental Epidemiology, Barcelona, Spain. iaguilera@ creal.cat
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Aguilera
authors.forename: Raquel
authors.initials: R
authors.lastname: Garcia-Esteban
authors.forename: Carmen
authors.initials: C
authors.lastname: Iñiguez
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Nieuwenhuijsen
authors.forename: Agueda
authors.initials: A
authors.lastname: Rodríguez
authors.forename: Montserrat
authors.initials: M
authors.lastname: Paez
authors.forename: Ferran
authors.initials: F
authors.lastname: Ballester
authors.forename: Jordi
authors.initials: J
authors.lastname: Sunyer
mesh_terms: D000293:Adolescent; D000328:Adult; D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity; D000397:Air Pollution / Q000009:adverse effects* / Q000032:analysis; D015331:Cohort Studies; D004781:Environmental Exposure; D005260:Female; D047109:Fetal Development / Q000187:drug effects; D006801:Humans; D006841:Hydrocarbons, Aromatic / Q000032:analysis / Q000633:toxicity; D007231:Infant, Newborn; D008297:Male; D009585:Nitrogen Dioxide / Q000032:analysis / Q000633:toxicity; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects / Q000000981:diagnostic imaging*; D013030:Spain; D014186:Transportation; D016216:Ultrasonography, Prenatal; D014504:Urban Health; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D006841:Hydrocarbons, Aromatic; D009585:Nitrogen Dioxide