A woman’s exposure to polluted air before pregnancy may increase the risk of heart defects in her baby, the American Heart Association reported, citing a study by scientists from Sichuan University.
Congenital heart defects are the leading cause of infant mortality worldwide. More than 80 percent of heart defects have no known cause, but previous studies suggest that environmental exposures may play a role.
Sichuan University analyzed data from more than 1.4 million babies born between 2014 and 2017 in 30 provinces and municipalities in China. 7,335 babies were born with heart defects. Researchers used satellite data to analyze a woman’s exposure to polluted air three months before conception and through the end of the first trimester. Increasing the average monthly exposure by every 10 micrograms per cubic meter increased the risk of having a baby with a heart defect by 2 percent.
The study proved for the first time that dirty air is dangerous for a baby even before conception. Moreover, the negative effects of air pollution were even greater when exposed before conception than when exposed in the first trimester.
It is unclear whether these findings would hold true in countries with less polluted air: in China, average concentrations of fine particulate matter PM2.5 in the air are 6.5 times higher than recommended by the World Health Organization.
The American Heart Association recommends that women planning a pregnancy use home air filters and wear face masks in places with dirty air.