Exposure to air pollution, even for a short term, may significantly increase the risk of miscarriages, a study has found. Air quality has been associated with numerous adverse health outcomes from asthma to pre-term birth. Researchers at the University of Utah in the US found women living along the most populous region in the state of Utah had a higher risk (16 per cent) of miscarriage following short-term exposure to elevated air pollution.
The study, published in the journal Fertility and Sterility, consisted of over 1,300 women (54 per cent Caucasian, 38 per cent Hispanic, and other/missing 8 per cent; average age 28 years). The women in the study sought help at the emergency department following a miscarriage (up to 20-weeks gestation) between 2007 to 2015.
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The team examined the risk of miscarriage during a three- or seven-day window following a spike in the concentration of three common air pollutants: small particulate matter (PM 2.5), nitrogen dioxide and ozone. The study excluded women who lived outside Utah. “We are really only seeing the most severe cases during a small window of time,” said Claire Leiser, from University of Utah. The results suggest there could be an increased risk for an individual.
The team found a 16 per cent increased risk in miscarriage for women exposed to elevated levels of nitrogen dioxide. Although small particulate matter does track with nitrogen dioxide, these results did not significantly associate with an increased risk of miscarriage. The team conducted a case cross-over study that estimated a woman’s risk of miscarriage multiple times in a month where air pollution exposure varied.