Air pollution may increase the risk of early pregnancy abortion

poor air quality is one of the main causes of disease. Numerous studies have shown that a mother's exposure to polluted air increases the risk of childbirth and may affect her health during pregnancy or even through her life. However, little is known about the relationship between miscarriage and air pollution in the early stages of pregnancy.
Liqiang, a professor at Beijing Normal University, and his co-researchers analyzed the clinical records of more than 250,000 pregnant women in Beijing over the past 10 years and found that air pollution exposure was associated with an increased risk of miscarriage during pregnancy. The results were published October 14 in the journal Nature-Sustainability.
the study is meant to remind pregnant women to take precautions consciously. On the other hand, it is hoped that people will take more active measures to improve air quality and better protect their health. Zhang Liqiang said.abortion means that the fetus has not yet taken shape or has died, but the placenta and embryonic tissue remain in the mother's womb. Zhang Liqiang introduced that the incidence of abortion in many developing countries is still high. In some countries, the rate is reported to be around 15 per cent. Since China liberalized the policy of having two children in 2016, the impact of the environment on pregnant women in old age has become more obvious.
To understand the effects of air pollution on abortions between pregnant women in The Beijing area, the researchers analyzed the clinical records of 255,668 pregnant women in the city from 2009 to 2017, including their level of education, occupation, residence and place of work, and calculated air pollution exposure levels per pregnant woman based on measurements from air monitoring stations near their place of residence and work (34 in total). The pollutants covered in the study included PM2.5 particulate matter, sulfur dioxide, ozone and carbon monoxide.
grouped pregnant women by age of conception, occupation and ambient air temperature. Of the pregnant women involved, 17,497 (6.8 per cent) experienced abortion. "We found that the risk of miscarriage was associated with the age of the pregnant woman, the high and low temperature of the outside world, and so on." Hou Wei, a doctoral student in the Department of Geosciences at Beijing Normal University, said. The study found higher rates of miscarriages associated with older mothers, female farmers and blue-collar workers over the age of 39. In all groups, exposure of pregnant women to a variety of air pollutants was associated with the risk of miscarriage.
also found that for all four contaminants, the increased risk of miscarriage was associated with an increase in pollutant concentrations, as well as the amount of time pregnant women were exposed to the contaminated environment. "Our study found a quantitative relationship between them." Zhang Liqiang said. This increase in risk is not linear, but nonlinear as pollutant concentrations increase.On the effects of category 4 air pollutants on audit abortion, Lin Jintai, co-author of the paper and an associate professor in the Department of Atmospheric and Ocean Sciences at Peking University's School of Physics and a doctoral tutor, said carbon monoxide had a particularly high impact, followed by sulfur dioxide.
" toxic substances may attack developing fetuses by inducing changes in immunity through the placenta. The author points out in the article.
carbon monoxide can interfere with the metabolism and transport function of the placenta, and after crossing the placenta barrier, the concentration in the fetus is even higher than that of the mother. In addition, environmental carbon monoxide is associated with carmolytic hemoglobin (COHb) and nuclear red blood cells. Too much COHb in the mother's body may cause the fetus to lack oxygen, resulting in the death of the fetus.
Zhang Liqiang, the concentration of PM2.5 in this statistics from more than 30 micrograms per cubic meter to more than 200 micrograms. However, because of the strong collinear relationship between PM2.5 and carbon monoxide, the authors did not distinguish between the two pollutants.
that long-term exposure to air pollution in pregnant women may mean a higher risk of miscarriage, still birth and birth defects. The authors also explore several possible causal mechanisms to explain this association. If the mother is exposed to PM2.5 for a long time, the pollutants will cross the mother-fetal blood barrier, affecting the growth and development of the fetus. Contaminants entering fetal blood may interact with their tissue composition, producing pathological effects that cause irreversible damage to fetal division cells and lead to hypoxia or immune damage during critical periods of fetal development. In addition, studies have observed changes in placental appearance genetics caused by air pollution during the third month of pregnancy. This suggests that the mother's exposure to air pollution may impair placental function.
, Zhang stressed that the study only demonstrated a correlation between air pollution and abortion, not a causal one. "While we were able to adjust many known risk factors associated with abortion, we could not rule out residual conferring factors because we could not control other factors, such as traffic noise." The author wrote in the article. In addition, the researchers said that due to the lack of relevant data, indoor air pollution on the impact of abortion is less studied, but indoor pollution and environmental pollution is highly related." fetal health affects the fate of a family and even a country. Lin Jintai said. Reducing the risk of fetal death is included in the United Nations Sustainable Development Goals, and linking air pollution to space-time variability in abortion can enhance scientific and policy understanding of the health of pregnant women in developing countries.
findings illustrate positive measures before pregnancy or the ability to prevent or reduce harmful pregnancies. At the same time, the study helps to understand the relationship between exposure to air pollution and a range of reproductive outcomes. "Pregnant women or people who want to get pregnant must protect themselves from air pollution, not only for their own health, but also for the health of the fetus." Zhang Liqiang said.
china is entering an aging society, and the study provides an additional impetus for the country to reduce environmental air pollution and raise birth rates, he said. Although China's environmental pollution has been reduced in recent years, the level of pollution is still very high and must be further reduced.
" study of the relationship between abortion and the environment is just the beginning. Lin Jintai said. Future work should explore the benefits of reducing air pollution for human health by modeling a wide range of environmental conditions using more data sources. (Source: Feng Lifei, China Science Journal)
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