Alcohol Use During Pregnancy: Risks and Consequences

pregnant mother with child resting on her belly
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Most women know about 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. Family doctors and OB-GYNs caution patients to avoid consuming alcohol while pregnant. But a recent study examined a risk that many may have overlooked: that consuming alcohol during pregnancy can affect the alcohol-related habits of offspring.

Due to ethical considerations, it’s difficult to study the effects of various behaviors, substances, and the effect of alcohol or substance use in pregnant women. As a result, the medical profession errs on the side of caution in making recommendations – and when it comes to alcohol, this generally translates to a blanket prohibition of alcohol during the entire pregnancy. However, these generalized pronouncements – absent specific data and recommendations – can come across as vague, pro forma, or paternalistic. A few years ago, prevailing opinion suggested the risks of alcohol had been exaggerated. Some proposed that moderate consumption – one glass a night, or only during the last trimester – might constitute an acceptable level of risk.

Due to these factors, contradictory messages emerged about alcohol use during pregnancy. As alcohol use has become more mainstream and less stigmatized, many women would be more convinced by 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, the data just wasn’t there.

Research Reveals the Effect of Alcohol In Utero and Beyond

A recent study, performed in the laboratory rodent model, addresses this data gap. The researchers, led by Nicole Cameron, an assistant professor of psychology at Binghamton University, designed the study to examine the effects of moderate alcohol consumption on offspring exposed to alcohol while in utero, as compared to a control group of laboratory rodents 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 these study subjects 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 subjects in the study, but on subsequent generations.

Transgenerational Affects of Prenatal Alcohol Exposure

After exposing the test subjects to alcohol, the researchers tested the response of their offspring to alcohol. They showed an increased preference for alcohol over water, as well as a reduced sensitivity to the effects. In other words, the juvenile test subjects inherited a high tolerance for alcohol. This suggests that what would be considered a relatively moderate level of alcohol – one glass of wine a day – ingested during pregnancy can predispose the next generation to develop problematic habits and behaviors. In addition, subsequent generations showed decreased sensitivity to the effects of alcohol. Consuming alcohol during pregnancy exposes the developing fetus to alcohol in utero, and this may increase the likelihood of developing alcohol use disorder (AUD).

Medical professionals know prenatal exposure to alcohol leads to biological changes in the brain. They’ve observed the effect 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 teenage humans exposed to alcohol while in utero, brain connectivity was consistent with impaired cognitive performance. The teenagers were compared to a control group who had had no exposure to alcohol in utero. This study – along with others – helped define the array of symptoms that define Fetal Alcohol Spectrum Disorder (FASD),  which include deficiencies in cerebral connectivity as well as impaired cognitive abilities.

The new study at Binghamton University underscores these previous results. Even more concerning, in the new study, the effect lasted three generations. The transgenerational nature of the effect suggests that transmittable genetic alterations cause the observed behavioral changes. The test subjects, when exposed to alcohol during pregnancy, not only passed on damaging effects to their offspring, but created genetic changes that predisposed further generations, compounding the damage.

New Research on Alcohol and Genes Needed

The next step, according to the researchers, is to isolate and study the actual genetic alterations involved in this transgenerational effect. While this work continues, the new results paint a concerning picture. They add further support to the idea that alcohol use during pregnancy is dangerous. Therefore, it’s of critical importance for pregnant women to think seriously abut this subject, and consult with their OB-GYN before consuming alcohol during the course of their pregnancy.