A recent research has found that pregnant women's contact with fine particulate matter from traffic may decrease their children's birth weight.
The National Research Centre for Environment and Health in Neuherberg near Munich conducted the study, together with colleagues from the French Institute for Health and Medical Research INSERM scientists at the GSF.
In this study, the scientists have focussed on the effects of the harmful particulate matter on unborn life. The study is the extension of the GSF's successful cooperation with the internationally renowned French research institution, with the common objective of tracing the causes of environment-related health disorders.
For the study, which has now been published online, data from the group study LISA were used, in which the influence of living conditions and behaviours on the development of the immune system and allergies is studied.
The researchers studied 1016 mothers and their children born in Munich between 1998 and 1999. All women included in the study had not moved out during the pregnancy. On the basis of a measuring campaign at 40 locations in the city of Munich, the concentrations of traffic-related atmospheric pollutants during pregnancy, including fine particulate matter (those with a diameter of less than 2.5 micrometers, PM2,5), could be modelled at the home address of the pregnant women.
The model took into consideration the distance of each home from streets, the population density near the home as well as the fluctuations in the concentration of the air pollutants over time during the pregnancies.
Using a detailed questionnaire, the study authors could unravel the influence of air pollutants from that of other factors known to influence birth weight. Specifically, maternal smoking, the height and weight of the mother before pregnancy, the educational level of the mothers as well as the duration of the pregnancy and the child's gender could be controlled for.
The proportion of newborns with a birth weight below 3,000 grams increased with rising concentrations of fine particulate matter (PM2,5) during pregnancy. A similar alliance was observed between the absorbance of fine particulate matter and birth weight. The absorbance of particulate matter is considered to be an indicator of the particles originating from traffic, and in particular from diesel vehicles.
Earlier American Studies had already suggested that fine particulate matter might influence the birth weight. But this is the first study to suggest so clearly that traffic-related air pollutants have an influence.
The biological mechanisms which could explain the influence of air pollutants on the development of the unborn child are not known as yet. Fine particulate matter consists of hundreds of chemical substances. It is believable that a minor fraction of the fine particulate matter reaches the blood through the lungs and influences the placenta or other organs which are responsible for regulating the growth of the foetus.
Studies from the US and Poland have for example shown that polycyclic aromatic hydrocarbons (PAH), which are produced during incomplete combustion processes, can reach the foetus and influence its growth.