Research in the US has found that moderate alcohol exposure during pregnancy may change how the brain develops and could influence drinking behaviour decades later.  

Heavy drinking during pregnancy can damage brain development, but the long-term effects of moderate alcohol exposure before birth are still unknown.  

In the study from the University of Wisconsin–Madison (UW-Madison), pregnant monkeys were exposed to alcohol, and researchers then followed the offspring for 20 years, into middle age. 

“The brain is complicated, and there are a lot of neurotransmitters. For alcoholism, there are many potential culprits, but dopamine is a big target for research,” said Alexander Converse, the study’s lead scientist at UW-Madison. 

When the offspring reached adulthood, the team used PET scans - a clinically used imaging technique that allows measurement of brain chemical activity - to examine the dopamine system before and after alcohol exposure. After, they introduced alcohol in a controlled manner, with six drinks per day for four months, followed by voluntary drinking. 

The study found that monkeys exposed to alcohol before birth drank more quickly and at higher rates as adults. Lower levels of dopamine D2 receptors, proteins that regulate dopamine signalling, were linked to faster drinking. Changes in another protein, dopamine transporter, which recycles dopamine in the brain, were associated with heavier drinking behaviour. 

“It just adds to the biological evidence that stress during pregnancy is something that as society, we should try to alleviate,” Converse added. 

The findings published in The Journal of Neuroscience further inform public health advice to avoid alcohol during pregnancy.