The wrong genes mean even moderate drinking in pregnancy can affect a child's IQ

December, 2012

A large study suggests that even a few drinks a week can negatively affect the developing fetus, but only if the woman has specific gene variants.

It’s always difficult in human studies to disentangle the effects of lifestyle factors. Alcohol is a case in point, and in particular the vexed question of whether any alcohol is safe during pregnancy. A new study, however, has avoided the complication of co-occurring lifestyle and environment factors by looking directly at genetic variants.

This study, believed to be the first substantial one of its kind, used genetic variation to investigate the effects of moderate (<6 units of alcohol per week) drinking during pregnancy among a large group of women and their children. Since the individual variations that people have in their DNA are not connected to lifestyle and social factors, the approach removes that potential complication.

The study, involving 4,167 children, found that four genetic variants in alcohol-metabolizing genes were strongly related to lower IQ at age eight. But this effect was only seen among the children of women who were moderate drinkers (heavy drinkers were not included in the study), pointing to the effect requiring exposure to alcohol in the womb.

Ten SNPs from four genes previously implicated in alcohol metabolism, intake, or dependency, were analyzed. Four SNPs (particular variants) were related to children’s scores on the cognitive test (WISC), of which three are rare and one quite common. There was an additive effect, with carriers of multiple ‘bad’ alleles being more affected.

There was some evidence that only drinking one or two drinks a week was not harmful to the fetus, but because the numbers of women were relatively small, and individual variability was high, this can’t be assessed with any great certainty.

The critical factor appears to be metabolism of alcohol, with mothers who are ‘fast' metabolizers being safer for their fetus than mothers who metabolize alcohol more slowly.

Mothers' alcohol intake was based on questionnaires completed when they were 18 weeks and 32 weeks pregnant. ‘Moderate’ was defined as between one and six drinks a week. All participants were of white-European origin.

Reference: 

Related News

A study following over 300 Mexican-American children living in an agricultural community has found that their prenatal exposure to organophosphate pesticides (measured by metabolites in the mother’s urine during pregnancy) was significantly associated with attention problems at age 5.

A study involving 125 women has found the first, direct human evidence that fetuses exposed to elevated levels of the stress hormone cortisol may have trouble paying attention or solving problems at 17 months.

An imaging study has revealed that children (aged 5-15) whose mothers abused methamphetamine and alcohol during pregnancy had structural abnormalities in the brain that were more severe than those seen in children whose mothers abused alcohol alone.

When a pregnant woman uses cocaine, it can interrupt the flow of nutrients and oxygen to the baby, putting such children at risk for premature birth, low birth weight and many other problems.

A five-year study involving 214 children born to healthy, non-smoking Caucasian women in Krakow, Poland, has found that those prenatally exposed to high levels of polycyclic aromatic hydrocarbons (PAHs) had a significant reduction in scores on a standardized test of reasoning abi

The nutrient choline is known to play a critical role in memory and brain function by positively affecting the brain's physical development through increased production of stem cells (the parents of brain cells).

A mouse study has found that the diet of a pregnant mother, especially in regards to choline, can change the epigenetic switches that control brain development in the fetus.

Pages

Subscribe to Latest newsSubscribe to Latest newsSubscribe to Latest health newsSubscribe to Latest news