According to a research published in the Nature Communications journal, particles of black carbon or soot can be found on the part of the placenta that feeds the developing fetus in the womb. This means that unborn babies are exposed to air pollution particles that come from burning fuel and motor traffic.
This research is the very first study to prove that the placental barrier can be permeated by air particles breathed in by the expectant mother. In every placenta analyzed, researchers were able to find thousands of tiny air particles per cubic millimeter of tissue.
There have been studies linking the exposure of mothers to dirty air and in the increased risk of miscarriages, premature births, and low birth weights. With this research, it established the connection that air particles might be the cause and not just the inflammatory response the air pollution produced in mothers.
The researchers examined 25 placentas from non-smoking women from Hasselt, Belgium. This location has particle pollution levels below the limit of the European Union. However, it is above the limit set by the World Health Organization.
With the use of high-resolution imaging, they were able to find black carbon particles on the fetal side in each of the placentas they were studying.
The placentas of mothers who lived rather closed to very busy main roads and who have been exposed to high levels of pollution during the pregnancies had the highest levels of particles. The average was around 20,000 nano particles per cubic millimeter.
The other mothers in the study who had been exposed to lower levels of pollution and who lived at least 1,600 feet away from the busy main roads, had lesser levels of particles in their placenta. The average was around 10,000 per cubic millimeters.
Apart from examining the placentas of expectant mothers, the study also looked into placentas from miscarriages. They were able to find particles even in 12-week old fetuses.
With this study, researchers say that the particles can travel to the placenta through the mother’s lungs.
The lead researcher, Professor Tim Narwot from Hasselt University in Belgium said: Our results demonstrate that the human placental barrier is not impenetrable for particles.”
“Further research will have to show whether the particles cross the placenta and reach the fetus,” adds Narwot.
With the presence of these particles in the fetal side of the placental barrier, it means that there is a likelihood that fetuses have been exposed. There is currently a study being made to determine if these particles can cause damage to the DNA.
The team who found black carbon particles in placentas are also found the same particles in primary school children.
In 2017, a study was published about finding an average of 10 million particles per milliliter in hundreds of nine-to-12-year-olds they have tested.
“It shows there is translocation of particles from the lungs to all organ systems,” said Nawrot.
The professor also adds: “It is really difficult to give people practical advice because everyone has to breathe. But what people can do is avoid busy roads as much as possible. There can be very high levels next to busy roads, but just a few meters away can be lower.”
In response to the result of the study, Professor Jonathan Grigg, a leading expert in the effects of air pollution on children, from the Queen Mary University of London, had this to say: “There’s very strong epidemiological evidence that maternal exposure to air-pollution particles is associated with adverse outcomes such as miscarriage.
“This is the beginning of showing that this is a ‘plausible mechanism’ that could be causing these effects,” adds Grigg.
“Small particles, such as through smoking, can cause considerable disease related to the placenta and these findings of particles in the placenta are a concern. Their possible effects on the baby and mother warrant further investigation,” chimed Andrew Shennan, professor of obstetrics at King’s College London.