Study Shows Even Light Drinking In Pregnancy Can Affect Baby’s Brain

While many pregnant women generally know of the risks involving drinking alcohol while pregnant, a new study is shedding light on the effect that even a small amount of the substance can have on a developing baby’s brain.

A recent MRI study showed that even minor to moderate amounts of drinking alcohol during pregnancy can alter a baby’s brain structure and postpone brain development. Drinking alcohol during pregnancy can open up the growing fetus to fetal alcohol spectrum disorders (FASDs).

If a baby is exposed to alcohol in utero, he or she can go on to have a scope of these FASD symptoms, such as learning disabilities, language and speech delays, problems seeing or hearing, heart, bone, and kidney issues, as well as physical limitations, according to the Centers for Disease Control and Prevention (CDC).

“It might be a very small risk associated with every glass you might drink during pregnancy, but you never know if that may be the one that pushes you over the edge,” co-author Dr. Marlene Stuempflen told Insider.

In the study, scientists looked at fetal MRI scans of 24 unborn babies who had been exposed to alcohol while in utero. When the MRIs were conducted, the babies’ gestational ages were 22 to 36 weeks. Mothers submitted anonymous answers to questions about alcohol in order to reveal the babies’ exposure to alcohol. 

“Seventeen of 24 mothers drank alcohol relatively infrequently, with average alcohol consumption of less than one alcoholic drink per week,” lead author Patric Kienast said. “Nevertheless, we were able to detect significant changes in these fetuses based on prenatal MRI.”

Three of the mothers said they had one to three drinks each week, two said they consumed four to six drinks each week, and one said she drink an average of at least 14 drinks each week. Six of them also said they engaged in binge drinking alcohol at least once while they were pregnant, which is defined in a press release as more than four drinks in one instance.

“We found the greatest changes in the temporal brain region and STS,” the study’s senior author Gregor Kasprian, said. “We know that this region, and specifically the formation of the STS, has a great influence on language development during childhood.”

In the fetuses who had been exposed to alcohol, their “fetal total maturation score (fTMS) was significantly lower than in the age-matched controls, and the right superior temporal sulcus (STS) was shallower,” the press release noted. “The STS is involved in social cognition, audiovisual integration and language perception.”

While it’s not clear how the babies will be impacted once they are born, Kienast said “we can strongly assume that the changes we discovered contribute to the cognitive and behavioral difficulties that may occur during childhood.”

“Pregnant women should strictly avoid alcohol consumption,” Kienast added. “As we show in our study, even low levels of alcohol consumption can lead to structural changes in brain development and delayed brain maturation.”

The CDC noted that there was no difference in how many pregnant women said they drank alcohol in 2019 and 2020, but in both years, around 14% to 15% of pregnant women said they drank alcohol and around 6% said they had engaged in binge drinking.

“Unfortunately, many pregnant women are unaware of the influence of alcohol on the fetus during pregnancy,” Kienast noted. “Therefore, it is our responsibility not only to do the research but also to actively educate the public about the effects of alcohol on the fetus.”

The study’s findings will be presented at the Radiological Society of North America’s annual meeting next week and have not been published yet.

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