Alcohol is a commonly abused substance that is responsible for a large number of accident-related injuries and deaths around the world. Alcohol abuse also causes illnesses such as cirrhosis, cancer, psychiatric disorders and stroke.
It is well established that alcohol exposure during pregnancy can have devastating effects on fetal development, including fetal alcohol syndrome (FAS), which is characterized by growth retardation, facial abnormalities and intellectual disabilities. However, this is only the tip of the iceberg, as most children exposed to alcohol in utero do not suffer from full-blown FAS. Many more children show signs of alcohol-related neurodevelopmental disorder, a broad range of abnormalities in brain function in the absence of other physical alterations.
Preclinical laboratory studies carried out at UNM have documented that exposure to low levels of alcohol during pregnancy damages the fetal brain. A team of investigators led by Daniel Savage, PhD, chair of the Department of Neurosciences, recently discovered that exposure to blood alcohol levels as low as 0.05 percent (the legal intoxication limit is 0.08 percent), alters performance of laboratory rats on tasks involving learning and memory processes.
Work in my lab has also provided strong evidence supporting that there is no safe level of alcohol consumption during pregnancy. We have found that alcohol potently affects normal communication among brain cells in the developing brain. This process is known as neurotransmission and it occurs via specialized connection areas called synapses, where chemicals (neurotransmitters) are released from one neuron onto another. Our studies have focused on a brain region known as the hippocampus, which is important for learning and memory.
In this brain region, we have found evidence of two potent stimulatory effects of alcohol that are only observed during development. First, we found that alcohol exposure during the third trimester-equivalent of pregnancy distorts a symphony of neuronal activity that is essential for normal synaptic maturation. Second, we observed that alcohol dramatically affects the production of compounds called neurosteroids, which are essential for normal brain development. Excessive levels of neurosteroids produce premature stabilization of synapses. We are currently investigating whether this leads to abnormal formation of neuronal circuits.
Importantly, both of these effects of alcohol can be observed at concentrations below the legal intoxication limit. Thus, ingestion of just one alcoholic beverage during late stages of pregnancy could impair normal neuronal maturation by excessively stimulating neuronal activity in immature neurons.
In spite of public health campaigns, a significant number of women continue to drink during pregnancy. In some cases, women drink while being unaware of their pregnancy during the first trimester. Other women are aware of the dangers of alcohol consumption during pregnancy but are unable to abstain because they are addicted to this substance. There are no effective medications available that can be safely used to aid in the recovery of alcoholic pregnant patients. Still other women think it is acceptable to drink small quantities of alcohol during pregnancy, such as having a glass of wine with meals. In some instances, this is reinforced by ignorance on the part of health care professionals regarding clinical evidence indicating that consumption of even small quantities of alcohol can have significant effects on fetal brain development.