Air quality has been associated with numerous adverse health outcomes from asthma to pre-term birth. Now new research from the United States shows that being exposed to polluted air even for a short while, carries a higher risk of miscarriage.
Researchers studied more than 1,300 women (average age: 28 years) who sought help in a hospital’s emergency department, following a miscarriage (up to 20 weeks gestation), between 2007 and 2015.
They examined the risk of miscarriage during a three- or seven-day window, following a spike in the concentration of three common air pollutants: fine particulate matter (PM 2.5), nitrogen dioxide and ozone, in a populous region that experiences short periods of poor air quality during colder months.
The researchers tracked air quality and compared it with patient outcomes.
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.
This approach removed other risk factors, like maternal age, from the study.
The scientists were unable to ascertain the age of the foetus at the time of the miscarriage and were unable pinpoint a critical period when the foetus may be most vulnerable to pollutants.
However, the team found a slight increased risk in miscarriage for women exposed to elevated levels of nitrogen dioxide (16 per cent for 10 parts per billion increase during the seven-day window).
Although fine particulate matter does track with nitrogen dioxide, these results did not significantly associate with an increased risk of miscarriage.
"As the planet warms and population booms, air pollution is going to become a bigger problem,” said Matthew Fuller, senior author and assistant professor of surgery. Women can manage the risk by using a N95 particulate respirator face mask to filter out pollutants or avoid outdoor physical activity on poor air quality days.
Women can also use filters to lower indoor pollution and, if possible, time conception to avoid seasonal episodes of poor air quality. The findings were published in the journal Fertility and Sterility. - Science Daily