(CN) – Pregnant women exposed to air pollution have an increased risk of miscarriage in the first trimester, according to new research released Monday.
A massive study of more than a quarter million pregnant women published in the journal Nature Sustainability finds that maternal exposure to polluted air increased the chances of a missed miscarriage.
Alternatively known as a silent miscarriage, it occurs when the fetus has died early in the pregnancy and embryonic tissues and the placenta remain. It isn’t easily detectable as it isn’t accompanied by symptoms of cramping and heavy bleeding like other miscarriages. It may occur in up to 15% of all pregnancies, according to researchers.
The study, led by Liqiang Zhang of China’s Beijing Normal University, examined the health records of 255,668 pregnant women in Beijing and calculated their level of exposure to polluted air, including particulates such as carbon monoxide and sulfur dioxide. About 2 million people die every year from ailments connected to air pollution in China, according to the World Health Organization.
In the study, scientists found that 6.8% of those pregnancies ended in a missed miscarriage, likely due to high exposure to polluted air. Previous studies have indicated exposure to air pollution by pregnant women can lead to “low birth rate, preterm birth, gestational hypertension and preeclampsia,” and other pregnancy complications.
“Pollutants entering the bloodstream of a fetus might interact with its tissue components to produce pathological effects, leading to irreversible damage to the dividing cells of the fetus,” the study states.
Researchers said those women with long-term exposure to polluted air often bore a greater risk.
“Mothers exposed to air pollution were more likely to have chromosomal abnormalities,” the study states. “Therefore, maternal long-term exposure to air pollution increased the chances of abortion/miscarriage, stillbirth and birth defects.”
Although air pollution remains high in China, the government has taken steps in recent years to reduce it, including the closure of factories and mills and switching over to more renewable, eco-friendly energy sources.