Heavy prenatal alcohol use impedes proper childhood brain growth
Heavy drinking during pregnancy disrupts proper brain development in children and adolescents years after they were exposed to alcohol in the womb, according to results of a recent study.
The study, supported by the NIH, is the first to track children over several years to examine how heavy exposure to alcohol in utero affects brain growth over time.
The researchers used MRI scans to study brain growth patterns in children whose mothers drank heavily while pregnant and compared them with normal patterns of development in children who were unexposed to alcohol before birth.
Based on the findings, the researchers reported that children with heavy alcohol exposure had decreased brain plasticity, which allows the brain to grow and remodel itself based on experience with the outside world. Such adaptation continues throughout life and is crucial to learning new skills and adapting to the environment.
During normal development, brain volume increases rapidly at a young age as new neural connections are formed, and then decreases in certain regions during adolescence as underused brain connections are cleared away to increase efficiency. Whereas unexposed children showed this pattern of robust growth and reduction in the brain’s outmost layer, known as the cerebral cortex, those heavily exposed to alcohol typically only lost cortical volume.
Among the 70 children in the study who had been heavily exposed to alcohol in utero (average of 13 drinks per week throughout the pregnancy), the pattern of static growth was most evident in the rear portions of the brain — particularly the parietal cortex, which is thought to be involved in selective attention and producing planned movement.
In addition, heavier alcohol exposure was linked to lower intelligence, greater facial abnormalities, and little change in brain volume between scans. Most children received two scans approximately 2 years apart. Participants ranged in age from 5 to 15 years.
About half of the alcohol-exposed children were given full physical examinations to determine whether they met the criteria for fetal alcohol spectrum disorder, or FASD. Of the 37 children examined, 23 were classified as having the disorder, which may be marked by a pattern of distinct facial features, intellectual disability, speech and language delays, and poor social skills.
The study findings may have implications for developing early treatments that could correct or improve these patterns of abnormal brain development.
“These findings further illustrate the need for early intervention, as they demonstrate that effective treatments may not only address current difficulties, but may also impact developmental trajectories during later childhood and adolescence in a positive way,” study researcher Catherine Lebel, PhD, a postdoctoral fellow in the department of neurology, University of California, Los Angeles, said in a press release from the NIH.
Disclosure: Lebel reports no relevant financial disclosures.