ABSTRACT
OBJECTIVES: Scant evidence is available on effects of air pollution on longitudinally measured fetal biometry, and thus it remains unclear as to whether there are critical windows of exposure or specificity of effects. Our objective was to examine the association between exposure to nitrogen dioxide (NO2) during pregnancy and fetal and neonatal anthropometry in a cohort of Spanish women. METHODS: Temporally adjusted land-use regression was used to estimate exposure to NO2 at home addresses. Biparietal diameter (BPD), abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW) were evaluated in each trimester by ultrasound. As neonatal outcomes, weight, length and head circumference were analysed. SD scores adjusted by gestational age, mother characteristics and fetus sex were calculated at 12, 20 and 32 weeks of gestation as well as at birth. The association between fetal growth and average exposure to NO2 in the relevant windows was investigated using regression models, adjusted for socio-demographic and lifestyle-related variables. RESULTS: Exposure to NO2 was inversely associated with BPD, AC and EFW at week 32 and with growth in these parameters in weeks 20-32. BPD and FL were also affected earlier, at week 20. NO2 levels above the median (38 µg/m3) reduced size at week 32 by around 9% in all parameters except for FL (6%). The critical windows of exposure were in early pregnancy, before 20 weeks. Exposure in this period was also inversely associated with neonatal length and head circumference. CONCLUSIONS: Maternal exposure to NO2 is associated with impaired fetal growth from mid-gestation onwards.
Subject(s)
Air Pollutants/toxicity , Air Pollution/adverse effects , Birth Weight/drug effects , Fetal Development/drug effects , Maternal Exposure/adverse effects , Nitrogen Dioxide/toxicity , Vehicle Emissions/toxicity , Air Pollutants/analysis , Air Pollution/analysis , Air Pollution/statistics & numerical data , Body Size/drug effects , Cohort Studies , Female , Humans , Infant, Newborn , Linear Models , Maternal Exposure/statistics & numerical data , Multivariate Analysis , Nitrogen Dioxide/analysis , Pregnancy , Prospective Studies , Ultrasonography, Prenatal , Vehicle Emissions/analysisABSTRACT
BACKGROUND: In utero tobacco exposure has been associated with adverse pregnancy outcomes but few studies have used longitudinal ultrasound measurements to asses the effects on fetal growth. The aim of this study was to examine the impact of active and passive smoking during pregnancy on fetal biometry in a cohort of Spanish women. METHODS: Biparietal diameter (BPD), abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW) were evaluated in each trimester of pregnancy. Detailed information on smoking and potential confounders was assessed by questionnaire. SD scores were calculated from longitudinal growth curves adjusted for gestational age and potential determinants of growth. Size was assessed by means of unconditional SD scores at 12, 20, 32 and 38 weeks of pregnancy, while growth between these points was assessed by means of conditional SD scores. The association between smoking and fetal growth was investigated by regression models and adjusted for sociodemographic and lifestyle-related variables. RESULTS: Maternal smoking was inversely associated with size of all parameters at weeks 32 and 38 and with growth in 20-32, 12-32 and 12-38 week intervals. In 32-38 weeks the effect was significant for AC and EFW. Environmental tobacco smoke (ETS) exposure was inversely associated with growth in BPD in all the intervals except 32-38 weeks. CONCLUSIONS: Active smoking during pregnancy was associated with a reduction in BPD, AC, FL and EFW from mid-gestation. ETS adversely affected BPD from early pregnancy.
