Drinking alcohol while pregnant: Less than 1 drink per week can cause 'significant' changes in the brains of fetuses
Drinking even small amounts of alcohol while pregnant—less than one drink per week—can impact fetal brain development.
A study presented at the annual meeting of the Radiological Society of North America is raising questions about the safety of consuming even the slightest amount of alcohol while pregnant, as researchers uncovered structural brain abnormalities on the MRI exams of fetuses exposed to as little as one alcoholic beverage per week during gestation. In some cases, these abnormalities were found to be significant.
"Unfortunately, many pregnant women are unaware of the influence of alcohol on the fetus during pregnancy," said lead author Patric Kienast, MD, a PhD student in the Department of Biomedical Imaging and Image-Guided Therapy, Division of Neuroradiology and Musculoskeletal Radiology at the Medical University of Vienna. "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 research team analyzed MRI exams of 24 fetuses (between 22 and 36 weeks gestation) with prenatal alcohol exposure, which was determined via the mothers’ responses to a questionnaire (the Pregnancy Risk Assessment Monitoring System).
When compared to age-matched controls, the alcohol-exposed group displayed significantly lower fetal total maturation scores (fTMS). Additionally, the researchers noted that the right superior temporal sulcus (STS)—an area of the brain associated with social cognition and language/speech processing and perception—was shallower in the alcohol-exposed group.
Out of the 24 mothers involved in the research, 17 reported drinking very little—less than one alcoholic beverage per week. Despite this, the fetuses of those mothers still displayed “significant changes” in their brains on MRI scans.
The researchers suggested that the fetal developmental delays observed in their work could be due to a delayed stage of myelination, which, in turn, could impact function of the nervous system. They explained that myelination is known to be associated with important developmental milestones in infants, such as rolling over, crawling and language processing.
Although it is not yet clear if or how these developmental delays in utero will impact babies after birth, Kienast cautions that women should “strictly avoid alcohol consumption” during pregnancy, as data indicate that even small amounts can interfere with fetal development.
"To assess this accurately, we need to wait for the children who were examined as fetuses at that time to get a little older, so that we can invite them back for further examinations," Kienast said. "However, we can strongly assume that the changes we discovered contribute to the cognitive and behavioral difficulties that may occur during childhood."
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In addition to her background in journalism, Hannah also has patient-facing experience in clinical settings, having spent more than 12 years working as a registered rad tech. She joined Innovate Healthcare in 2021 and has since put her unique expertise to use in her editorial role with Health Imaging.