Women who breathe polluted air during pregnancy may be more likely to have children who develop high blood pressure, a US study suggests. Fine particulate matter of 2.5 microns or less (PM 2.5) is a form of air pollution produced by motor vehicles and the burning of oil, coal and biomass and has been shown to enter the circulatory system and negatively affect human health. Researchers examined 1,293 mothers and their children who were part of the large ongoing Boston Birth Cohort study.

Noel Mueller, assistant professor at Johns Hopkins University in the US and senior author of the study published in the journal Hypertension, said, “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. High blood pressure during childhood often leads to high blood pressure in adulthood and hypertension is the leading cause of cardiovascular disease.”

The examined data on 1293 mother-child pairs and assessed kids’ blood pressure at check-ups from ages three to nine years old. The researchers found that children exposed to higher levels of ambient fine-particulate pollution in the womb during the third trimester were 61% more likely to have elevated systolic blood pressure in childhood compared to those exposed to the lowest level.

Mueller said, “We believe that when pregnant women breathe air with high levels of fine particulate matter, it causes an inflammatory response that alters genetic expression and foetal growth and development on the pathway to high blood pressure in childhood.” She further added, “I think the take home message for pregnant women is not that you should change your residence but rather that you might consider avoiding highly polluted areas during pregnancy, particularly during heavy bouts of physical activity, which is important to keep up during pregnancy.”

High blood pressure is a major risk factor for cardiovascular disease and a leading cause of disability contributes to an estimated 7.5 million deaths worldwide each year, researchers noted in the journal Hypertension. Previous research has linked air pollution exposure in the womb to an increased risk of birth defects including abdominal malformations and what’s known as hypospadias, an abnormality in boys that occurs when the opening of the urethra doesn’t develop on the tip of the penis and instead forms on the shaft or on the scrotum.

(The above story first appeared on LatestLY on May 15, 2018 09:59 AM IST. For more news and updates on politics, world, sports, entertainment and lifestyle, log on to our website latestly.com).