Pollution exposure as a fetus increases risk for elevated BP in childhood

Fetuses exposed to higher levels of air pollution during their mother’s third trimester of pregnancy have a higher risk of elevated blood pressure in childhood, according to a new study published online May 14 in the American Heart Association’s journal Hypertension .

“Exposure to ambient air pollution has been associated with greater risk of elevated blood pressure in adults and children,” wrote lead author Noel T. Mueller, PhD, MPH, with Johns Hopkins University Bloomberg School of Public Health in Baltimore, and colleagues. “Recent evidence suggests that air pollution exposure in pregnancy may also portend increased risk for the next generation; however, few studies have examined this relationship.”

The researchers sought to determine the effects of breathing fine particulate matter of 2.5 microns or less (PM2.5) during pregnancy can affect the fetus’ health outcome later in life.

They conducted a study of 1,293 women in the Boston Birth Cohort. Information on the cohort was collected between 1998 and 2012. Researchers collected medical information on the cohort’s children who had follow-up visits between ages 3 to 9.

Systolic blood pressure was considered elevated if it was in the highest 10 percent of children the same age nationally. The investigators adjusted for factors that influence childhood blood pressure including birthweight and maternal smoking.

They found children who were exposed to higher levels of ambient fine-particulate pollution in utero during the third trimester had a 61 percent greater chance of exhibiting elevated systolic blood pressure in childhood. The researchers also determined an association between higher exposure to air pollution and elevated blood pressure regardless of birth weight.

A woman’s exposure to fine particulate matter before pregnancy was not associated with blood pressure in her offspring.

The authors noted that the results reinforce the importance of reducing emissions of PM2.5 in the environment because it not only harms those directly exposed. It is also associated with a negative health impact on the fetus and could potentially result in negative outcomes later in life.

“Ours is one of the first studies to show breathing polluted air during pregnancy may have a direct negative influence on the cardiovascular health of the offspring during childhood,” Mueller said. “High blood pressure during childhood often leads to high blood pressure in adulthood and hypertension is the leading cause of cardiovascular disease.”