Air pollution link to miscarriage risk

By Julie Griffiths on 18 December 2018

Short-term exposures to air pollution can raise miscarriage risks by 16%, study finds. 

The retrospective study by the University of Utah consisted of more than 1300 women with an average age of 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.

The team compared the incidence of miscarriages to the levels of ozone, nitrogen and fine particulate matter (PM 2.5) in the air on the preceding days. 

After carefully controlling for all other miscarriage risk factors, there were 16% more miscarriages in the three to seven days when air quality was particularly poor in Salt Lake City, Utah, which, at the time, had the worst air in North America. 

The team found a slight increased risk in miscarriage for women exposed to elevated levels of nitrogen dioxide (16% for 10 ppb increase during the seven-day window). Although small particulate matter does track with nitrogen dioxide, these results did not significantly associate with an increased risk of miscarriage.

However, University of Utah research analyst Claire Leiser warned caution should be exercised in looking at the results.

‘We are really only seeing the most severe cases during a small window of time,’ she said.
Nevertheless, Leiser notes the results suggest there could be an increased risk for an individual. 

Their research only captured women who sought help at an emergency department at one hospital in the region. It does not account for women who may have sought outpatient care through their obstetric or primary care providers.

The study was published in the journal Fertility and Sterility here.