Researchers at Children's Hospital Boston and the Boston Medical Center used MRI (magnetic resonance imaging) scans to study the brains of 35 children, average age 12, who were exposed to the substances while in the womb.
"We found that reductions in cortical gray matter and total brain volumes were associated with prenatal exposure to cocaine, alcohol or cigarettes," study first author Dr. Michael Rivkin, a neurologist at Children's Hospital Boston, told Biology News.
The decrease in brain volume is greater when more substances were exposed to prenatal baby.
Earlier studies were mostly limited to children with fetal alcohol syndrome that revealed brain effects.
It is estimated that more than one million babies born every year in the U.S. were exposed to at least one of these substance abuse while in the womb.
The study authors said that health care providers should offer pregnant women comprehensive care to help them reduce the use of all harmful substances. And public health campaigns shouldn't ignore the risks of some substances while focusing on others, since the greater the number of total prenatal exposures, the more likely there will be harmful and lasting effects on a baby's developing brain.
The study was published in the April issue of the journal Pediatrics.
