A child’s IQ suffers from even minimal levels of exposure to alcohol while in his/her mother’s womb, according to a new study conducted by researchers from the Universities of Bristol and Oxford and published in the journal PLOS ONE.
At present, theories on drinking alcohol moderately during pregnancy vary. Certain official recommendations state that women who are pregnant should completely refrain from drinking, while others say that moderately drinking is okay. Prior research has made for controversial and conflicting opinions on the matter, as well as conflicting evidence regarding how children’s IQs are effected by alcohol intake among their mothers.
The report claims that this may be due to the fact that it is often hard to differentiate between whether a child’s IQ is affected by the moderate alcohol intake of his/her mother or other lifestyle and social elements, including diet, smoking, age, affluence and education.
For the new study, researchers utilized the Children of the 90s study (ALSPAC) data taken from more than 4,000 mothers and their children. The new trial is thought to be the first to use genetic variation to analyze the impact that mothers’ moderate drinking (less than 1-6 units of alcohol a week) has on their child’s IQ. Using genetic variation is ideal because each woman has different DNA, which is not linked to lifestyle factors, therefore, this method takes away that possible complication.
In the 4,167 children involved in the study, a strong link was found between 4 genetic alternatives in genes which metabolize alcohol and lower IQ at the age of 8 years old. For each genetic modification a child had, their IQ was found to be 2 points lower. However, this was only observed in children whose mothers reported moderate drinking while pregnant. On the other hand, this link was not found at all among children whose mothers reported no drinking while pregnant, indicating that there is a direct association between alcohol exposure in the womb and damage to a child’s IQ. The report notes that the study did not involve excessive drinkers.
When alcohol is consumed, ethanol is turned to acetaldehyde by a cluster of enzymes. Differences in people’s genes that ‘encode’ these enzymes results in variations in their capability to metabolize the ethanol. Therefore, in people whose genes metabolize slowly, alcohol levels can reach higher points and last longer than those whose enzymes metabolize quickly.
Experts say that ‘fast’ metabolism of ethanol defends against damage to infants’ brain development, due to the fact that smaller amounts of alcohol are exposed to the fetus. However, the exact happenings remain unknown.
Earlier research has been based on evidence observed by other researchers, however, this is not concrete. Observational studies tend to claim that moderate drinking is better than not drinking at all. This is because pregnant women who drink lightly while pregnant have been reported to be educated, healthy and not likely to smoke, which are common factors associated with a child’s chance of having a higher IQ, therefore covering the potential risk factors that alcohol exposure could give to the child.
The new trial observed moderate alcohol consumption among more than 4,000 mothers by utilizing a method called Mendelian randomization, a tool which analyzes the associations between exposure and later outcomes by using genetic variants that alter levels of exposure and are not affected by lifestyle habits.
The participants’ intake levels were determined by a survey they were given to complete when they were 18 weeks pregnant. It involved questions regarding the average amount consumed, and how often the women consumed alcohol prior to becoming pregnant, during the first trimester, and in the two weeks prior to the first time they felt their child move. One drink was considered one unit of alcohol for this study.
When the mothers were around 32 weeks pregnant, they were asked to complete a second survey, which questioned the average amount of drinking the mothers had consumed on weekdays and weekends. Each mother who said they had consumed alcohol, regardless of whether it was less than one unit a week during the first trimester or when she felt the baby first move, was considered as a drinker while pregnant.
At weeks 18 and 32, the mothers were also asked how many days during the previous month they had consumed two pints of beer, or the same amount in alcohol. Each woman who said that they had done this, even if it was only once in a while, was considered a binge drinker in this particular study and was no longer allowed to be involved in the trial.
At age 8, the children’s IQs were tested by researchers utilizing the Wechslet Intelligence Scale for Children, from which an average age adjusted complete score was made.
Dr. Sarah Lewis, lead author of the study, commented on the findings:
“Our results suggest that even at levels of alcohol consumption which are normally considered to be harmless, we can detect differences in childhood IQ, which are dependent on the ability of the foetus to clear this alcohol. This is evidence that even at these moderate levels, alcohol is influencing foetal brain development.”
Dr. Ron Gray, from the University of Oxford and research leader, concluded, “This is a complex study but the message is simple: even moderate amounts of alcohol during pregnancy can have an effect on future child intelligence. So women have good reason to choose to avoid alcohol when pregnant.”
Written by Christine Kearney