Fetal Alcohol Syndrome (FAS)

Medically Reviewed on 3/20/2023

Facts you should know about fetal alcohol syndrome (FAS)

  • Combined 2015 to 2016 data from the National Survey on Drug Use and Health (NSDUH) show that 10% of pregnant women 15 to 44 years of age drank alcohol in the past month. About 3% admitted to binge drinking during pregnancy. ("Binge drinking" in women is defined as four or more "hard alcohol" drinks consumed at one time. Male binge drinking is consuming five or more "hard alcohol" drinks consumed at one time.) Among women aged 18 to 45 years of age who were not pregnant, 55.5% drank alcohol in the past month, and 38.4% binge drank.
  • Infants of mothers who drank during pregnancy may experience a spectrum of consequences that range from "fetal alcohol effects" (FAE), alcohol-related birth defects (ARBD), partial fetal alcohol syndrome (PFAS), and fetal alcohol syndrome (FAS). Fetal alcohol syndrome is the most severe.
  • Some children sustain no obvious side effects of maternal alcohol consumption during pregnancy. Exactly why this occurs is a paradox.

What is fetal alcohol syndrome?

In 1996, the Institute of Medicine defined fetal alcohol syndrome as "a pattern of physical, behavioral and cognitive abnormalities in individuals exposed to alcohol while in the womb. The association between these findings and maternal use of alcohol during pregnancy is well documented. To establish the diagnosis of fetal alcohol syndrome, specific criteria must be met. These include (1) documentation of three characteristic facial abnormalities, (2) documentation of smaller than expected prenatal and/or postnatal length, weight, and head circumference growth parameters, and (3) documentation of central nervous system abnormalities including measurable reduction in brain growth and function and behavioral/academic abnormalities, (4) other congenital malformations of the heart, kidneys, eyes, and hearing loss. These criteria will be further described later in this article.

What if I drank heavily before I knew I was pregnant?

Most alcohol use by pregnant women occurred during the first trimester. Alcohol use was lower during the second and third trimesters than during the first (4.2% and 3.7% vs. 17.9%, respectively). These findings suggest that many pregnant women are getting the message and not drinking alcohol. It is speculated that the larger frequency of first trimester drinking may have occurred prior to the woman becoming aware of her pregnancy.

What causes fetal alcohol syndrome?

Alcohol is rapidly transported via placental blood flow from mother to fetus and is known to cause miscarriage and birth defects. Within two hours of maternal ingestion, fetal alcohol blood levels are similar to maternal alcohol blood levels. There is no established relationship between the amount of alcohol consumed and side effects sustained by the infant. This puzzling observation may reflect the maternal rate of alcohol breakdown via her liver.

It has been observed that alcohol consumed at any time during pregnancy may be associated with severe and permanent consequences. First trimester pregnancy alcohol ingestion is linked to the characteristic facial abnormalities of FAS as well as a reduction of intrauterine growth rate. Alcohol consumption during the second trimester also contributes to lower IQ, growth retardation in length and birth weight, as well as cognitive deficits of reading, spelling, and math. Third trimester alcohol consumption amplifies retardation in birth length and ultimate adult height potential.

What are risk factors for fetal alcohol syndrome?

The Surgeon General and the Secretary for Health and Human Services recommend total abstinence from alcohol for women planning pregnancy, at the time of conception and throughout the entire pregnancy. No safe level of prenatal alcohol consumption has been documented. Multiple other countries have established similar guidelines.

Other risk factors include the following:

  1. Binge drinking (four or more drinks in one sitting) is more problematic than consumption of the same amount of alcohol spread out over time (such as four back-to-back drinks at one sitting vs. one drink per day for four days).
  2. Older maternal age (over 35 years old)
  3. African-American or Native-American ethnic groups and a listing of many varied background elements (lower socioeconomic status, smoking, unmarried, unemployed, use of illicit drugs, maternal history of sexual or physical abuse, history of incarceration, having a partner or family member who drinks heavily and experiencing psychological stress or having a mental health disorder)


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What are symptoms and signs of fetal alcohol syndrome?

Infants with the diagnostic criteria to establish fetal alcohol syndrome exhibit the following characteristic findings:

  1. Unique facial characteristics: What does a person look like with fetal alcohol syndrome? They have a thin upper lip; a uniquely smooth ridge between the upper lip and nose (the "philtrum"); and a smaller than normal space between the upper and lower eyelids ("palpebral fissure")
  2. Growth delay: smaller than expected length, weight, and head circumference measurements during both intrauterine and post-birth growth
  3. Central nervous system abnormalities: (a) structural (small brain size and slower than expected growth); (b) functional (global developmental delay in motor skills, language acquisition and utilization, problems with attention/hyperactivity, social skill deficiencies, impaired memory and judgment, and poor impulse control, etc.)
  4. Children with fetal alcohol syndrome commonly have birth defects that include heart defects, as well as abnormalities of the kidneys, eyes, and hearing loss.

How do physicians diagnose fetal alcohol syndrome?

The risk for potential fetal alcohol syndrome is established during the first prenatal visit. Pregnant women are questioned regarding behavioral risk factors, including illicit drug usage, alcohol consumption, smoking, and other high-risk behaviors. Several screening questionnaires may be utilized; these include (1) T-ACE, (2) TWEAK, and (3) AUDIT-C. There are several laboratory blood studies that may indicate recent use or repeated and excessive alcohol abuse.

Prenatal indicators for potential alcohol use would note smaller than expected growth in length, weight, and head measurements. Slower than expected head growth is a reflection of subnormal brain growth. Once born, the above-noted facial changes will lead the pediatrician to consideration of the diagnosis of FAS. The myriad of developmental and cognitive delays discussed above will also stimulate consideration of FAS in children who are failing in cognitive advancement or with associated behavioral deficiencies.

Do all alcoholics have babies with FAS?

In addition to fetal alcohol syndrome, there are three other conditions associated with fetal exposure to alcohol. These include the following:

  1. Requirements for partial FAS with confirmed maternal alcohol exposure: confirmed fetal alcohol exposure; characteristic facial abnormalities; either growth retardation, brain neurodevelopmental findings, other unexplained behavioral abnormalities and alcohol-related birth defects
  2. Requirements for alcohol-related birth defects: confirmed maternal alcohol exposure, birth defects and alcohol-related neurodevelopmental disorders
  3. Requirements for alcohol-related neurodevelopmental disorder: confirmed maternal alcohol exposure and either neurodevelopmental abnormalities or other unexplained behavioral abnormalities

What is the treatment for fetal alcohol syndrome?

While no cure exists for fetal alcohol syndrome, early intervention programs have been shown to lessen the impact of language, motor, and cognitive impairments. Such aggressive programs utilize physical therapy, occupational therapy, speech therapy, and educational therapy to maximize benefit. Adolescents and adults may benefit from programs dealing with academic, legal, and psychiatric problems.

What are the complications and long-term effects of fetal alcohol syndrome?

Many of the issues faced by infants and children with FAS continue into adolescence and adulthood. These may include:

  1. problems with "regulation" (sleeping, attention, and arousal),
  2. learning disorders,
  3. impairment with vision and hearing,
  4. mental retardation,
  5. deficits in memory, reasoning, and judgment.

More unique to adolescents and adults are issues with sexual behavior, legal problems, and substance abuse. It is often observed that the characteristic facial features noted in infancy and childhood seem to "soften" with age. A small-sized head and short stature do continue into adulthood.

Does FASD get worse with age?

As noted in the above discussion, an individual with FAS may experience a lifelong litany of both physical and intellectual challenges. Early intervention programs and multi-therapy programs (including physical therapy) may often lessen the impact of the diagnosis.

Is it possible to prevent fetal alcohol syndrome?

Yes! Avoid all alcohol consumption while planning for conception and during pregnancy.

Is it safe to consume alcohol and breastfeed?

The concentration of alcohol in breast milk is very similar to maternal blood levels. Potential consequences include a reduction in breast milk consumption, alteration of newborn sleep and wake cycles, and possible delay of motor development at 1 year of age.

Where can people find more information about fetal alcohol syndrome?

Centers for Disease Control and Prevention, "Fetal Alcohol Spectrum Disorders (FASDs)"

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Medically Reviewed on 3/20/2023
Institute of Medicine. Stratton, K., C. Howe, and F. Battaglia, eds. Fetal Alcohol Syndrome: Diagnosis, Epidemiology, Prevention, and Treatment Institute of Medicine. Washington, DC; National Academy Press, 1966.

Lyons Jones, Kenneth, et al. Smith's Recognizable Patterns of Human Malformation, 5th ed. Philadelphia, Pa: WB Saunders Co, 1997.

Thachray, H. and C. Fifft. "Fetal Alcohol Syndrome." Pediatrics in Review 22.2 February 2001.

United States. Centers for Disease Control and Prevention. "Fetal Alcohol Spectrum Disorders (FASDs)." Apr. 5, 2021. <http://www.cdc.gov/ncbddd/fasd/index.html>.