A baby is heavily protected by the placenta in the pregnant woman’s womb.
What does placenta do?
The placenta helps exchange of nutrients from the mother’s blood to the baby’s blood, without allowing the two to mix. It also allows some antibodies that confur immunity to be transferred from the mother to the baby (IgG antibodies are transferred; IgM antibodies are not). Waste products from the baby, such as creatinine, urea, and uric acid are passed across the barrier to the mother’s blood, from where they are excreted.
The role of placenta is crucial in protecting the baby’s delicate systems. When placental protection fails, the fetus becomes vulnerable.
Air pollution and pregnancy
Previous research has showed that pregnant women, living in polluted areas, are more prone to pregnancy-related problems. Typical issues are restricted fetal growth, premature birth, low birth weight, infant mortality, and childhood respiratory problems.
The European Union (EU) recommends a limit to various components of air pollution. For example, a type of superfine particles, called PM2.5, that are grade-1 carcinogens (highly cancer causing), should be below 25 µg/m3. However, even in areas with PM2.5 below those levels, there is an increased risk of low birth weight babies.
It was long assumed that the mother’s body would stop the air pollution particles much before they reach the placenta. So, the mechanism by which air pollution affects the fetus is not known.
New research findings
New research presented at the European Respiratory Society International Congress showed that when pregnant women inhale polluted air, carbon particles in it are able to get into mother’s bloodstream, and then into the fetus’ placenta.
There are placental macrophage cells that engulf any harmful bacteria and confer immunity to the baby. In the study, those cells were found to contain carbon soot particles, which were perhaps from the air pollution, coming in through the mother’s lungs. If the pollution particles can reach the placental macrophage cells, it indicates that the air pollution can affect the baby.
These particles in the placental cells were noticed even when the pregnant women lived in air deemed safe by EU safety standards.
If air pollution particles can reach the baby’s placenta, even at levels considered safe as per the EU standards, then pregnant women need to be extra careful.
While it might be safe for the mother to be living in such safe air areas, it may not be enough for the baby. The pregnant woman may need to live in still lower pollution levels, for the sake of the fetus.
While a pregnant woman can not stay out of the polluted air for 24 hours, she should consider air purifiers in the house, and definitely in the bedroom, where she spends a significant amount of time.
First published on: 19th September, 2018