Researchers from Northwestern University’s Feinberg School of Medicine have just released a study that may help explain why some fetuses of moms who drink suffer negative outcomes, while others do not.
The debate over whether and how much pregnant women can safely drink is a complex one, with some recent studies actually showing that kids of mothers who drink lightly in pregnancy have improved outcomes in certain measures. Meanwhile, as researchers noted in the current study, alcohol consumption in pregnancy is still considered one of the “most prevalent non-genetic causes of neurodevelopmental deficits.”
Here’s what the Northwestern researchers say might help explain some of the confusion:
The crux of their findings is that certain fetuses have a form of the gene Dio3 (which codes for an enzyme that controls thyroid hormone) that makes them vulnerable to the effects of alcohol.
Certain versions of the Dio3 gene make for a low production of the thyroid hormone-stabilizing enzyme, which then translates into an excess of thyroid hormones. When a mother passes on a version of this gene to her boy fetus, the brain’s hippocampus (important for learning and memory) becomes vulnerable to the effects of even moderate amounts of alcohol.
The researchers gave rat mothers in the study the human equivalent of two to three glasses of wine a day. The fetuses who had inherited this specific version of the Dio3 gene showed significant deficits in social behavior and memory, while others were unaffected.
This is an example of the principle that one size does not fit all when it comes to environmental influences on the brain. Moderate alcohol (although I would classify two to three drinks a day as more than moderate) will affect each baby uniquely based on his or her particular genetic makeup. Same goes for many of the other influences like diet and environmental exposures in pregnancy.
How do you feel about the safety of alcohol in pregnancy?