Particles of black carbon – or soot – can cross the placenta, a study has found.
The Nature Communications research is the first direct evidence the particles can get into the part of the placenta that feeds the developing foetus.
It could be the first step to explaining why high pollution is linked to an increased risk of miscarriage, premature birth and low birth weights.
Experts said women could take measures like avoiding busy roads.
But they warned tackling air pollution could only be achieved at a “policy level”.
How the placenta works
The placenta is made up of two parts. The foetal placenta, made from the same tissue that forms the foetus, and the maternal placenta which is made from tissue from the mother’s uterus.
Oxygen and nutrients are able to