Even a small dose of alcohol during pregnancy can increase the risk of alcoholism in the next three generations, according to a study published in Alcoholism: Clinical and Experimental Research.
Previous studies have shown that alcohol use and related disorders pose a significant threat to global health. Exposure to moderate amounts of alcohol in utero or during early life puts humans at greater risk for alcohol abuse in adolescence and adulthood.
Factors affecting teen drinking habits are varied and complex. They include the desire to engage in risk-taking and rebellious behavior, as well as the wish to impress and to sustain popularity among peers.
Alcohol exposure can begin early, during pregnancy, through breastfeeding or when participating in festive occasions. One study shows that 39% of 8-10-year-old children in Pennsylvania had drunk or sipped alcohol.
The contexts in which alcohol is consumed have been linked to the quantities and rates of consumption, affecting the decision to partake of a glass of wine with dinner or indulge in a binge-drinking session.
Scientists have found a significantly higher rate of alcohol use disorder among adolescents born to mothers who consumed three or more drinks when pregnant, compared with those whose mothers did not drink.
An increased propensity to drink is thought to be linked to prenatal alcohol exposure (PAE) altering the neurophysiological response to the challenge of alcohol.
Between 10-15% of American women are estimated to drink some alcohol during pregnancy.
Just four glasses can affect offspring
Nicole Cameron, assistant professor of psychology at Binghamton University in New York, and colleagues collaborated with Michael Nizhnikov, of South Connecticut University, to investigate the effects of alcohol consumption during pregnancy on alcohol-related behavior in future generations.
To examine the effect, they gave pregnant rats the equivalent of one glass of wine each day for 4 consecutive days, during the rat equivalent of the second trimester in humans.
They then tested young offspring of both genders for water or alcohol consumption over two subsequent generations, to find out if rats whose mothers or grandmothers had consumed alcohol while pregnant were more likely to consume it themselves.
To evaluate sensitivity to alcohol, they looked at the righting reflex, or the ability to return the body to its default position, in this case, from lying down to standing up.
Adolescent male rats received a high dose of alcohol, which rendered them unresponsive and drunk on their backs. The team measured how long it took the rats to recover their senses and get back on their four paws.
Results showed that rats whose mothers or grandmothers consumed the equivalent of one glass of wine four times during the pregnancy, were more likely to have a preference for alcohol themselves, and their sensitivity to alcohol was altered compared with those who had not been exposed.
This implies that if a mother drinks even a small amount during pregnancy, there is a greater chance that her children and grandchildren will become alcoholic.
Cameron told Medical News Today:
"Alcohol is a dirty drug that may affect multiple systems. We have selected this period of exposure because, in rats, many important developments take place at that time including dopaminergic axons from the midbrain reaching the cortical plate and the development of GABAergic neurons in cortical layer IV. Since the cortex plays a principal role in mediating ethanol-induced effects, these two events are particularly important in the study of alcohol sensitivity and abuse."
Other studies into the effects of alcohol exposure during pregnancy have focused on fetuses that were directly exposed or on cellular activity over multiple generations, but they have not looked at alcohol-related behaviors over the second or third generation.
The next step will be to identify how this effect passes through the generations by looking at the effects of alcohol on the genome and epigenome, which are the molecules that control gene translation.
MNT reported recently that the very first drink a person experiences will cause a neurological change in the brain.
When we asked Cameron whether she would expect the same effect to manifest more strongly in someone who was exposed during pregnancy, she replied: "Yes, because the brain is developing, I expect the effect to be more potent in the fetus."