Teratogens: Alcohol

Teratogens: Alcohol

One of the most commonly used teratogens is alcohol. Because half of all pregnancies in the United States are unplanned, it is recommended that individuals of child-bearing age take great caution against drinking alcohol when not using some form of birth control and when pregnant (Surgeon General’s Advisory on Alcohol Use During Pregnancy, 2005). Alcohol consumption, particularly during the second month of prenatal development, but at any point during pregnancy, may lead to neurocognitive and behavioral difficulties that can last a lifetime.

Fetal Alcohol Spectrum Disorders (FASD) is a collection of developmental disorders affecting offspring that result from an individual drinking alcohol while they are pregnant. These disorders range from mild learning disabilities, to memory and attention deficits, to birth defects, to developmental delays, to serious behavior disorders, to sudden infant death syndrome. Drinking during pregnancy is the leading known cause of preventable birth defects in the Western world. To prevent these birth defects, the answer is simple. A pregnant individual should not drink alcohol while they are pregnant or even if they might become pregnant because…

• There is no known amount of alcohol that is safe during pregnancy.
• There is no known time during pregnancy that is safe to drink.
• And, there is no drink that contains alcohol that is safe.

Fetal Alcohol Spectrum Disorders are found across all social, economic, and racial groups. This spectrum of disorders includes the following:

• Fetal Alcohol Syndrome (FAS)
  • Includes a pattern of facial abnormalities, insufficient brain growth, and distinct behavioral and cognitive (thinking abilities) abnormalities
• Alcohol-Related Birth Defects (ARBD)
  • Includes minor facial abnormalities, structural or functional defects of organs (heart, skeleton, kidneys, eyes, or ears), and cognitive and behavioral abnormalities
• Alcohol-Related Neurodevelopmental Disorders (ARND)
  • Consists of insufficient brain growth and distinct behavioral and cognitive abnormalities

Clearly, there is a vast spectrum of abnormalities associated with prenatal alcohol exposure. The range of these abnormalities is dependent on many factors, including the amount of alcohol consumed, the developmental stage of pregnancy when exposed, and the pregnant individual’s pattern of drinking. Other factors that affect the severity of FASD include the nutritional status of the pregnant individual, any use of drugs during pregnancy, and their genetics.

Physical Features Associated with Fetal Alcohol Spectrum Disorders

The physical features resulting from exposure of the fetus to alcohol have been well-described. Several are quite typical of children with FAS and ARBD. These include, 1) a specific set of facial abnormalities (discussed below), 2) other organ structural defects, 3) prenatal and/or postnatal growth deficiency (below the 10th percentile for height or weight), and 4) a reduced head circumference. These features can occur in any combination in any child (although not all) exposed to alcohol prenatally. An example of the types of facial abnormalities is shown in the figure below.

Facial Abnormalities associated with FAS and ARBD

Scientists have studied how alcohol causes developmental abnormalities in facial structure in animal models. For example, look at a picture of the faces of a normal mouse fetus and a mouse fetus that was exposed to a high dose of alcohol by its mother. The facial abnormalities are very similar to humans with FAS or ARBD.

While very evident during childhood, many of these facial abnormalities tend to become less apparent with age, and adults with FAS may no longer show the classic facial characteristics. Some of the structural features can cause functional problems as well. For example, there can be reduced vision due to retinal malformations.

Not all people exposed to alcohol during pregnancy show facial abnormalities. Some people have very prominent facial abnormalities, and others look perfectly normal.

Some organs inside the body fail to develop normally. And our most precious organ, the brain, clearly shows structural abnormalities with the help of technologies such as magnetic resonance imaging (MRI). However, they all still suffer the neurocognitive and behavioral abnormalities discussed below.

Neurocognitive and Behavioral Abnormalities Associated with FASD

In addition to the structural problems, the effects of alcohol on a fetus can produce a host of other symptoms throughout childhood and adulthood, notably neurocognitive or behavioral problems and learning disabilities. While not all children exposed to alcohol prenatally exhibit these symptoms, the most common ones are listed below.

Children who have FASD exhibit some combination of these cognitive and behavioral problems, regardless of when the mother drinks alcohol. Often, these children are mislabeled with other disorders such as Attention Deficit Hyperactivity Disorder (ADHD) because of some of the similarities in their behavioral problems.