Stress in pregnancy makes women more vulnerable to smoking and air pollution, research suggested in July 2017.
Highly-stressed pregnant women who smoke are significantly more likely to have low-birth weight babies than more relaxed expecting smokers, a study review found.
The combination of high stress and air pollution also increases the risk of having a low-birth weight baby, the research adds.
Senior author Professor Tracey Woodruff, from the University of California, San Francisco, said: ‘It appears that stress may amplify the health effects of toxic chemical exposure, which means that for some people, toxic chemicals become more toxic.’
Co-author Professor Rachel Morello-Frosch, from the University of California, Berkeley, added: ‘The bottom line is that poverty-related stress may make people more susceptible to the negative effects of environmental health hazards, and that needs to be a consideration for policymakers and regulators.’
The researchers analysed 17 human studies and 22 animal trials that investigated the link between stress, chemicals and foetal development.
Stress was defined by factors such as socioeconomic status.
Professor Morello-Frosch added: ‘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.’