Air pollution is behind growing concerns about asthma attacks keeping more children out of school.

But did you know air pollution can take a toll even before the child is born? So says a study in the journal JAMA Psychiatry. It finds that the fetuses of pregnant women exposed to a common air pollutant are at an elevated risk of brain damage and developmental problems.

“They tend to be fidgety and hyperactive and very impulsive, so they leap before they look,” Dr. Bradley Peterson, of Children’s Hospital Los Angeles and the lead author of the study, told the Los Angeles Times.

The researchers linked in-utero exposure to polycyclic aromatic hydrocarbons (PAH), which are found in vehicle exhaust and power-plant emissions, to reduced white matter in children’s brains. White matter is crucial for cognitive functions such as attention and focus. PAH exposure after birth also correlated with diminished white matter — “a double hit,” as Peterson calls it.

Preventing harm

The good news for prenatal care is that small changes can make a difference in the health of a child. “Even if you reduce your exposure from moderately high to moderate levels, it’s going to have a beneficial effect on the developing fetus,” Peterson told Medical Daily.

In China, where high levels of air pollution also have been shown to affect prenatal development, measures to clean the air during the 2008 Beijing Olympics resulted in higher birth weights among babies born shortly after the games.