A new study has found that babies born to women who use cocaine, alcohol or tobacco during pregnancy may have brain structure changes that continue into early adolescence.
Using magnetic resonance imaging (MRI) brain scans, researchers at the Children's Hospital Boston and the Boston Medical Center studied brain structure of 35 young adolescents prenatally exposed to cocaine, marijuana, alcohol or tobacco.
The children aged 12 years at the time of imaging, were part of a historic cohort of children assembled by Deborah Frank, MD at Boston Medical Centre and followed them since birth.
"We found that reductions in cortical gray matter and total brain volumes were associated with prenatal exposure to cocaine, alcohol or cigarettes," said Dr Michael Rivkin, neurologist at Children's Hospital Boston.
"Importantly, although volume reductions were associated with each of these three prenatal exposures, they were not associated with any one of these substances alone after controlling for other exposures," he added.
While analysing the MRI images, the researchers noticed that the effects were additive, the more substances a child was exposed to in utero, the greater the reduction in brain volume.
Previous studies have also shown brain effects of prenatal alcohol exposure.
Researchers initially set out to study cocaine exposure, but they were struck by the finding of brain effects of prenatal tobacco exposure.
"Approximately 20 percent of women who smoke continue to smoke during pregnancy," said Rivkin.
"From the vantage point of preventive health care, it is important to determine the consequences on brain structure of prenatal exposure to cigarettes, alone and in combination with other substances," he added.
The study was funded by the National Institute on Drug Abuse.