Environmental Health Perspectives: Prenatal Exposure to Traffic-Related Air Pollution and Ultrasound Measures of Fetal Growth in the INMA Sabadell Cohort

Prenatal Exposure to Traffic-Related Air Pollution and Ultrasound Measures of Fetal Growth in the INMA Sabadell Cohort

Article
Formal Correction: This article has been formally corrected to address the following errors.

Inmaculada Aguilera1,2,3,4, Raquel Garcia-Esteban1,2,3, Carmen Iñiguez3,5, Mark J. Nieuwenhuijsen1,2,3, Àgueda Rodríguez6, Montserrat Paez7, Ferran Ballester3,5, Jordi Sunyer1,2,3,4

1 Centre for Research in Environmental Epidemiology, Barcelona, Spain, 2 Municipal Institute of Medical Research (IMIM-Hospital del Mar), Barcelona, Spain, 3 Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública, Barcelona, Spain, 4 Pompeu Fabra University, Barcelona, Spain, 5 Centre for Public Health Research, Conselleria de Sanitat, Generalitat Valenciana, Valencia, Spain, 6 Servei de Ginecologia i Obstetrícia, Hospital Parc Taulí, Sabadell, Spain, 7 Centre d’Atenció Primària Sant Fèlix, Sabadell, Spain


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.

Editor's Summary
Numerous studies have reported that traffic-related air pollution is associated with intrauterine growth restriction, low birth weight, and preterm birth, but studies to determine the most harmful pollutants and the most susceptible periods for exposure have been inconclusive. Aguilera et al. (p. 705) studied exposure to nitrogen dioxide (NO2) and aromatic hydrocarbons in association with fetal growth among 562 pregnant women in the Spanish INMA Sabadell study cohort. Exposure to aromatic hydrocarbons during early pregnancy was inversely associated with growth in biparietal diameter during weeks 20–32, but none of the other fetal growth parameters were associated with exposure to air pollution during pregnancy. Associations were stronger among women who spent < 2 hr/day in nonresidential outdoor locations, resulting in statistically significant associations between NO2 and growth in head circumference during weeks 12–20 and growth in abdominal circumference, biparietal diamter, and estimated fetal weight during weeks 20–32. The authors conclude that exposure to traffic-related air pollutants during early pregnancy may affect fetal growth during mid-pregnancy.

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Environmental Health Perspectives: Prenatal Exposure to Traffic-Related Air Pollution and Ultrasound Measures of Fetal Growth in the INMA Sabadell Cohort

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