According to a new study, there is evidence of a link between ozone exposure and premature births and pre-eclampsia, a dangerous pregnancy condition.
The study, recently published in BMJ Open, an online journal of the British Medical Association, showed that women who have greater exposure to ozone during the first trimester of pregnancy had a statistically significant increase in the risk of premature birth and pre-eclampsia, the Wall Street Journal reports. Pre-eclampsia is characterized by an increase in the pregnant woman’s blood pressure that can lead to seizure, stroke, and death of the mother or baby.
The study was based on medical records of nearly 121,000 Swedish women; their ozone exposure in the first trimester of pregnancy varied due to weather or time of year. Ozone is formed on warm, sunny days from vehicle exhaust and other pollution, making the exposure to ozone greater during warmer months, when people are outside more. While the overall risk of either condition is small, the study reports a 4 percent increase in the risk of both premature birth and pre-eclampsia for every 10-microgram increase in ozone per cubic meter of air. The researchers statistically factored out such things as maternal age, asthma and body weight, and seasonal differences in air pollutants, variables that could be involved.
David Olsson, a doctoral student in occupational and environmental medicine at Umea University and one of the study’s authors, suggested that pregnant women minimize their ozone exposure by avoiding heavily trafficked areas on hot, dry days. But he also noted that spending too much time indoors during pregnancy reduces the health benefits of being outside. Mr. Olsson suggested the need for environmental changes to “lessen the burden of traffic pollution,” the Wall Street Journal said.
The study was funded by the Swedish government and used government data on pollution levels.