Researchers of the Mixed Unit in Epidemiology and Environmental Health of the Foundation for the Development of the Health and Biomedical Research of the Valencian Community (FISABIO), the Universitat Jaume I (UJI) and the Universitat de València have studied the impact of the atmospheric pollution in the fetal growth during pregnancy.
The results show that the maternal’s exposure to nitrogen dioxide (NO2), which is directly related with the pollution produced by the traffic, is associated with a lower growth of the foetus. Said exposure is more harmful when it takes place on the first phases of the pregnancy.
The study, carried out on the framework of the INMA project (Childhood and Environment), has been carried out on the cohorts of Valencia, Sabadell, Asturias, and Guipúzcoa.
In the study ultrasounds to 2.478 foetuses were carried out at 12, 20, and 34 weeks gestation, in which were measured the biparietal diameter (the distance that exists between the two cranial parietal bones), the length of the femur, abdominal circumference, and the estimated foetal weight. These measures were completed with the anthropometric exploration of the baby at birth.
To estimate the exposure to NO2 of the mothers during pregnancy, it was carried out a measurement campaign in each one of the fields of study. Specifically, in Valencia, 93 passive sensors were distributed in the field of study to obtain an exposure measure based on the residence.
The results of this research indicate that the exposure to more than 34 μg/m3 of NO2 (with respect to the babies that are exposed to lower doses) is associated with a reduction of the foetal size of a 7% regarding the biparietal diameter; of a 6% in the weight; and of a 4% in the abdominal girth.
The most consistent effect is observed in the biparietal diameter, between the 20 and 34 weeks of pregnancy. The weakest effect is observed in the length of the femur and only occurs at the beginning of the pregnancy.
“So far the foetal growth has been studied specially in base to the birth weight, and therefore, it is not possible to know when, within the foetal phase, the effect started. Nevertheless, we could examine, through the ultrasound scans, in which moment the effects start being visible”, emphasises the doctor Carmen Íñiguez, researcher of the Mixed Unit in Epidemiology and Environmental Health of FISABIO, the UJI and the Universitat de València.
“When working with repeated measures of the same child, we can know when a stunted growth was starting to be produced and see if this effect is permanent or can be compensated. Also, we compare with the size state of the child in prior moments instead of with population data, which allows for a better evaluation of the growth”, adds the doctor Íñiguez.
“Knowing when the impact occurs -specifies the FISABIO’s researcher- is important from the clinical point of view to know the pathophysiological mechanisms that run the association”.
Likewise, the negative association of this exposure with the biparietal diameter and the foetal weight has been significantly bigger in smoker mothers in comparison with non-smoker mothers.
For this study it has been followed a rigorous work methodology that started with the measuring of atmospheric pollution and the elaboration of exposure maps, the collection of direct information during pregnancy, paying attention to all the variables that may influence (as the dietary habits of the mother, the anthropometry of the parents, the habits respect to the tobacco and the alcohol consumption, the social class, the level of education, the employment situation, etc.), the collection of information of the ultrasound scans and the elaboration of personalised growth models for each child considering the growth constitutional potential of each one of them.
The results of this study, compiled in the article “La exposición prenatal a la contaminación del aire se asocia al crecimiento fetal” (“The prenatal exposure to the air pollution is associated with the foetal growth”) have been published in the journal Environmental Health Perspectives. The article is signed by the FISABIO researchers Carmen Íñiguez, Ana Esplugues, Olga Costa, Marisa Estarlich, Mario Murcia, Maria José López Espinosa and Ferran Ballester, coordinator of the Area of Environment and Health of FISABIO-Public Health and professor of the Universitat de València.
“We are a very wide group of researchers who work in this project. This article responds to the team work of many people involved in our centre and in other centres that also are part of the INMA Project. Without them, and specially without the collaboration of the parents and the involved families, it would have been impossible developing this study”, indicates Carmen Íñiguez.
In the article have also collaborated researchers of the Biomedical Research Consortium in Epidemiology and Public Health (CIBERESP), the Research Centre in Environmental Epidemiology (CREAL), the Institute Hospital del Mar d’Investigacions Mèdiques, the University Pompeu Fabra, the Area of Public Health of the Basque Government, Biodonostia Institute for Health Research, the University of Oviedo and the University of the Basque Country.
On the INMA Project and the cohort in Valencia
INMA – Childhood and Environment is a research network of Spanish groups that aims to study the role of the most important environmental pollutants in the air, water and in the diet during the pregnancy and start of life, and their effects in the child growth and the development.
In October 2003 it was carried out the pilot study for the creation of the cohort INMA in Valencia. 855 women from the province of Valencia were recruited.
The newborn babies were monitored throughout the childhood. It was carried out a visit after one year of life in which the neurological development, the anthropometry, the respiratory health and the environmental exposures were evaluated.
Additionally, the levels of airborne pollutants in their houses were measured in half of the children (inside and outside), by installing dosimeters during 15 days.
At the age of two it was carried out a telephone interview, and at the age of four an appointment was made at La Fe Hospital to evaluate the dietary habits, the growth, and to obtain biological samples (urine, hair, and blood) for the measurement of nutrients and exposure to environmental pollutants.
Last update: 3 de august de 2015 12:04.
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