Brain Changes Found in Fetuses of Alcohol-Using Moms

CHICAGO — Super-resolution imaging of the brains of fetuses of women who have consumed excessive alcohol during pregnancy appeared to show two areas that were abnormal, a researcher reported.

Statistical analysis found an increased volume in the corpus callosum and a decreased volume in the periventricular zone when compared with the brains of fetuses of non-drinking women, said Gregor Kasprian, MD, of the Medical University of Vienna.

He and his colleagues compared 12 different brain structures, but found differences in just those two areas, Kasprian said at the Radiological Society of North America annual meeting, conducted this year both in person and online.

“Fetal alcohol syndrome is a worldwide problem in countries where alcohol is freely available,” he noted. “It’s estimated that 9.8% of all pregnant women are consuming alcohol during pregnancy, and that number is likely underestimated.”

Fetal alcohol syndrome is the most severe form of the group of fetal alcohol spectrum disorders that result from alcohol exposure during pregnancy. Babies born with the disorders may have specific physical features, learning disabilities, behavioral problems, or speech and language delays. Approximately one in 70 pregnancies with alcohol exposure results in fetal alcohol syndrome, Kasprian said.

“There are many postnatal studies on infants exposed to alcohol. We wanted to see how early it’s possible to find changes in the fetal brain as a result of alcohol exposure,” he explained.

Asked for his perspective, Max Wintermark, MD, chief of neuroradiology at Stanford University in California, said: “This very interesting paper highlights the risk of alcohol consumption during pregnancy. What we still need to know, however, is whether these changes are reversible over time, and how they correlate with the cognitive development of these children once they are born.”

“I do not think that we know the relationship between the structural changes and the development of the children,” he added. “There might be a link, but I would also hope that the children could recover from this prenatal exposure.”

For the study, the team recruited 500 pregnant women who had been referred for a fetal magnetic resonance imaging (MRI) for clinical reasons. On an anonymous questionnaire, 51 of the women admitted to consuming alcohol during their pregnancy. The questionnaires used were part of the Pregnancy Risk Assessment Monitoring System, a surveillance project of the CDC and health departments, and the T-ACE (tolerance, annoyance, cut down, eye-opener) screening tool, a measurement of four questions that identify risk drinking.

After the researchers eliminated some of the fetal MRI scans for reasons such as structural brain anomalies or poor image quality, the final study group consisted of 26 fetal MRI exams from 24 alcohol-positive fetuses and a control group of 52 gender- and age-matched healthy fetuses. At the time of imaging, the fetuses ranged in age from 20 to 37 weeks.

Use of super-resolution imaging allowed the researchers to create one dataset to reconstruct each fetal brain. The investigators then completed an analysis of 12 different brain structures, computing the total brain volume and segment volumes of specific brain compartments.

“One of the main hallmarks of our study is that we investigated so many smaller sub-compartments of the brain,” commented co-author Marlene Stuempflen, MD, also of Medical University of Vienna. “This is the first time that a prenatal imaging study has been able to quantify these early alcohol-associated changes.”

Stuempflen noted that since the corpus callosum is the main connection between the brain’s two hemispheres, it is fitting that this central structure is affected, because the clinical symptoms of fetal alcohol spectrum disorders are highly heterogenous and cannot be pinpointed to one specific substructure of the brain. “The changes found in the periventricular zone, where all neurons are born, also reflect a global effect on brain development and function,” she said.

Finding a thicker corpus callosum in the alcohol-positive fetuses was surprising because the corpus callosum is thinner in infants with fetal alcohol spectrum disorders, Kasprian noted.

“It appears that alcohol exposure during pregnancy puts the brain on a path of development that diverges from a normal trajectory. Fetal MRI is a very powerful tool to characterize brain development not only in genetic conditions, but also acquired conditions that result from exposure to toxic agents,” he said.

But, he told MedPage Today, “Our data was collected within the past 3 years; thus the follow-up range is too short to make any assumptions on the behavioral effects of alcohol exposure. Further, the changes we were able to detect were located in brain regions, which could functionally contribute to a broad range of cognitive or behavioral problems in different domains. We will try to follow up our cohort — as far as this is possible from an ethical standpoint as this data is extremely sensitive — and see if these results are also predictive for individual behavioral outcomes.”