Public health: Air pollution linked to ‘silent miscarriage’ pregnancies in Beijing

Maternal exposure to air pollution has been linked to an increased risk of missed miscarriage in the first trimester, according to a study of over 250,000 pregnant women in Beijing between 2009 and 2017, published in Nature Sustainability.

Poor air quality is a leading cause of global disease burden. Previous research has consistently indicated that maternal exposure to air pollution contributes to increased risks of adverse birth outcomes such as low birth weight, preterm birth, gestational hypertension and preeclampsia, and may also affect maternal health during pregnancy and over the course of a woman’s life. However, little is understood about how exposure to air pollution relates to missed miscarriage. Also known as a ‘silent miscarriage’, a missed miscarriage is when a fetus has not formed or has died, but the placenta and embryonic tissues remain in the mother’s uterus.

Liqiang Zhang and colleagues analysed the clinical records of 255,668 pregnant women in Beijing and computed the air pollutant exposure level of each pregnant woman based on measurements at the air monitoring stations nearest to her residence and place of work. Air pollutants considered for the study included particulate matter with diameter below 2.5 μm, sulfur dioxide, ozone and carbon monoxide. The authors grouped pregnant women by age at conception, occupation and air temperature. Among the participating pregnant women, 17,497 (6.8%) experienced missed miscarriage. The authors found that in all groups exposure to higher concentrations of these pollutants was associated with higher risk of missed miscarriage in the first trimester.

Further research is needed to understand the specific mechanism by which air pollution affects the fetus.

doi: 10.1038/s41893-019-0387-y

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