Certain chemicals are associated with an increased risk of stillbirth within two to four days of exposure, according to a study from researchers at the California Office of Environmental Health Hazard Assessment, or OEHHA.
The paper — written by OEHHA Air and Climate Epidemiology Chief Rupa Basu and OEHHA research scientist Brian Malig along with Varada Sarovar, who was a UC Berkeley graduate student at the time — builds on previous research by Basu, who previously looked into the correlation between long-term exposure and stillbirth.
“We’ve seen different findings between the long-term and the short-term studies,” Malig said. “And there’s some inconsistency between our study and the other short-term studies that are out there within the U.S. I definitely think that it needs to be further investigated.”
The study was conducted by looking at periods of high chemical exposure and then looking to match this data with other data about women who had a stillbirth within a month of the exposure. Between 1,203 and 13,018 stillbirth cases were used for the study’s various analyses, according to the paper.
Short-term exposure to some chemicals, including coarse particles, ozone and sulfur dioxide, was identified in the study as being linked to stillbirth.
Most of the stillbirths associated with the chemicals studied are due to complications in childbirth, although sulfur dioxide is also associated with physical defects at birth, Basu said.
Significantly, Malig noted, there was little indication that major socioeconomic discrepancies exist among mothers who lose their child, although efforts to stratify the results too much by racial or economic categories ran into problems as a result of the relatively limited data.
“Interestingly enough, when we stratified by education, we were actually seeing that the association was stronger in women with higher educational attainment,” Malig said.
Basu urged people to be mindful of pollution, especially traffic emissions, which contain significant amounts of nitrogen dioxide.
“If you can mitigate exposure, try to mitigate exposure during pregnancy, because we’re seeing short- and long-term effects,” Basu said.