Research Report: Alcohol Use During Pregnancy

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Most women understand the risks associated with consuming alcohol during pregnancy. Public education regarding Fetal Alcohol Spectrum Disorder (FASD), for example, has come a long way since the syndrome was first identified. OB-GYN providers counsel most pregnant women to avoid consuming alcohol during pregnancy. A recent study honed in on a risk that many may have overlooked: consuming alcohol during pregnancy can affect the alcohol-related habits of children.

Due to ethical considerations, studying the effects of various behaviors and substances in pregnant women presents significant challenges. The medical profession tends to err on the side of caution in making recommendations. When it comes to alcohol, this generally translates to a blanket prohibition of alcohol during the entire pregnancy. However, recent work suggests that the risks of alcohol have been exaggerated. Now, some suggest moderate consumption — one glass a night, or only during the last trimester – constitutes an acceptable level of risk.

All this means that we, the general public, and women in particular, regularly receive contradictory messages about alcohol use during pregnancy.

New Research on Long-Term Effects

As alcohol use among women becomes less stigmatized, women need a specific and detailed assessment of the risks, backed by research that investigates each stage of pregnancy and assesses the risks at different levels of consumption.

But, due to lack of research, detailed data at this level of specificity is not there – yet.

A recent study, conducted in a laboratory rats, may begin to address this data gap. A group of researchers, led by Nicole Cameron, an assistant professor of psychology at Binghamton University, designed an experiment to examine the effects of moderate alcohol consumption on offspring exposed to alcohol while in utero, as compared to a control group of rats with no exposure to alcohol during that time.

The pregnant animals in the study received a daily dose of alcohol – adjusted for size, the approximate equivalent of one glass of wine – during what would be the second trimester in humans. Because rats have a short gestational period relative to humans, and their offspring mature relatively quickly, it was possible to study the effects of this amount of alcohol, not only the immediate offspring of the rats in the study, but on subsequent generations.

Transgenerational Effects of Prenatal Alcohol Exposure

After exposing the pregnant rats to alcohol, the researchers tested the juvenile rats’ response to alcohol. The offspring showed an increased preference for alcohol over water, as well as a reduced sensitivity to the effects. In other words, the juvenile rats inherited a high tolerance for alcohol. This suggests a relatively moderate level of alcohol – one glass of wine a day – ingested during pregnancy predisposes the next generation to problematic habits and behaviors. It also suggest lowered sensitivity to the effects of alcohol in subsequent generation.

Medical professionals have long known prenatal exposure to alcohol leads to changes in the brain, and these effects have been measured in humans. As part of a study carried out by an international group of researchers, scientists looked at the brains of adolescents using a brain imaging technique called magnetoencephalography (MEG). In the brains of teenagers exposed to alcohol while in utero, brain connectivity was consistent with impaired cognitive performance, as compared to a group who had had no exposure to alcohol in utero. Along with other studies, this helped define the array of symptoms that define FASD, which include deficiencies in cerebral connectivity as well as impaired cognitive function.

Alcohol During Pregnancy: Caution Still Advised

The new study at Binghamton University underscores these previous results.

In the sample of rats studied, the effect lasted three generations. The transgenerational nature of the effect suggests that transmittable genetic alterations caused the behavioral changes. The rats, when exposed to alcohol during pregnancy, not only passed on the behaviors to their offspring, but created genetic changes that predisposed further generations to compound the damage.

The next step, according to the researchers, is to isolate and study the actual genetic alterations involved in this transgenerational effect. While this work remains to be done, these new results add further support to the recommendation that no amount of alcohol can be considered safe during pregnancy.