Stress raises the chances that pregnant women exposed to toxic chemicals will have a low birth weight baby, a new study found.
“It appears that stress may amplify the health effects of toxic chemical exposure, which means that for some people, toxic chemicals become more toxic,” said Tracey Woodruff, a University of California – Berkeley professor and lead author of the study.
This is the first study to examine the combined effects of stress and environmental toxic chemical exposures on fetal growth, researchers said.
High-stress pregnant women who smoked were about twice as likely to have a low birth weight baby as low-stress smokers, the study found. Stress was quantified by factors such as socioeconomic status or years of paternal education.
The effects of air pollution on low birth weight were heightened when combined with stress, the researchers found. Exposure to ambient fine particulate matter, a type of air pollution, increased the risk of African-American women having a low birth weight baby compared to those who were white.
The study, published in the journal PLOS ONE, was based on a systematic review of 17 human studies and 22 animal studies examining the links between chemicals, stress and fetal development.
“While the evidence on the combined effects of chemicals and stress is new and emerging, it is clearly suggestive of an important question of social justice,” said co-author Rachel Morello-Frosch at UC Berkeley.
Poverty-related stress may make people more susceptible to the negative effects of environmental hazards, she said.
“That needs to be a consideration for policymakers and regulators,” Morello-Frosch said.