Unborn foetuses could already have pollution particles in their lungs, brain and other vital organs in their first trimester, a new study has shown.
Research undertaken by the University of Aberdeen and Hasselt University in Belgium found that black carbon, or soot particles, can be transferred from the mother to her unborn baby and could affect the development of the foetus.
The findings, which the scientists describe as ‘very worrying’, are published in Lancet Planetary Health and show that the exposure of the foetus is directly proportional to the mother’s exposure to air pollution particulates.
Black carbon is an air pollutant released from internal combustion engines, coal-fired power plants, and other fossil fuel sources. The detrimental effects of these particles on health are widely known and have been linked to the chemicals they are coated with during combustion. Maternal exposure to black carbon has been associated with stillbirth, preterm birth, low-weight babies and disturbed brain development, with consequences persisting throughout life.
The scientists looked at two populations, one in Belgium and one in North East Scotland. In Belgium, 60 randomly selected mother-neonate pairs from mothers giving birth at the East-Limburg Hospital in Genk as part of the ENVIRONAGE (Environmental Influences on Ageing in Early Life) study were selected for sampling. Mothers who had ever smoked were excluded.
In Scotland, data was analysed from 36 foetuses of terminated but normally progressing pregnancies in women of 16 years of age or over as part of the SAFeR (Scottish Advanced Fetal Research) study. The foetuses had gestational ages of between seven and twenty weeks. To determine whether nanoparticles could reach a foetus during gestation, the scientists used white light to detect black carbon particles within the samples.
The presence of black carbon particles in cord blood linking the unborn baby and its mother confirmed the ability of these particles to cross the placenta and enter the fetal circulation system.
Professor Paul Fowler from the University of Aberdeen said: ‘We all worried that if nanoparticles were getting into the foetus, then they might be directly affecting its development in the womb. What we have shown, for the first time, is that black carbon air pollution nanoparticles not only get into the first and second trimester placenta but then also find their way into the organs of the developing fetus, including the liver and lungs.’
He added: ‘What is even more worrying is that these black carbon particles also get into the developing human brain. This means that it is possible for these nanoparticles to directly interact with control systems within human fetal organs and cells.’
The study provides direct evidence that maternally inhaled carbonaceous air pollution particles cross the placenta to reach the fetal circulation and are passed in proportion to the mother’s exposure to air pollution; however, the mechanisms by which this happens are still unclear.
Professor Tim Nawrot from Hasselt University added: ‘We show in this study that the number of black carbon particles that get into the mother are passed on proportionally to the placenta and into the baby. This means that air quality regulation should recognise this transfer during gestation and act to protect the most susceptible stages of human development.’