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Fetal-Alcohol Syndrome (FAS)

A.D.A.M. Medical Encyclopedia.

Fetal alcohol syndrome

Alcohol in pregnancy; Drinking alcohol during pregnancy; Alcohol-related birth defects; Fetal alcohol effects; FAS

Fetal alcohol syndrome is growth, mental, and physical problems that may occur in a baby when a mother drinks alcohol during pregnancy.

Causes, incidence, and risk factors:

Using or abusing alcohol during pregnancy can cause the same risks as using alcohol in general. However, it poses extra risks to the unborn baby. When a pregnant woman drinks alcohol, it easily passes across the placenta to the fetus. Because of this, drinking alcohol can harm the baby’s development.

A pregnant woman who drinks any amount of alcohol is at risk for having a child with fetal alcohol syndrome. No “safe” level of alcohol use during pregnancy has been established. Larger amounts of alcohol appear to increase the problems. Binge drinking is more harmful than drinking small amounts of alcohol.

Timing of alcohol use during pregnancy is also important. Alcohol use appears to be the most harmful during the first 3 months of pregnancy; however, drinking alcohol any time during pregnancy can be harmful.


A baby with fetal alcohol syndrome may have the following symptoms:

  • Poor growth while the baby is in the womb and after birth

  • Decreased muscle tone and poor coordination

  • Delayed development and problems in three or more major areas: thinking, speech, movement, or social skills

  • Heart defects such as ventricular septal defect (VSD) or atrial septal defect (ASD)

  • Problems with the face, including:

    • Narrow, small eyes with large epicanthal folds

    • Small head

    • Small upper jaw

    • Smooth groove in upper lip

    • Smooth and thin upper lip

Signs and tests

A physical exam of the baby may show a heart murmur or other heart problems. As the baby grows, there may be signs of delayed mental development. There also may be problems with the face and bones.

Tests include:

  • Blood alcohol level in pregnant women who show signs of being drunk (intoxicated)

  • Brain imaging studies (CT or MRI) after the child is born

Expectations (prognosis)

The outcome for infants with fetal alcohol syndrome varies. Almost none of these babies have normal brain development.

Infants and children with fetal alcohol syndrome have many different problems, which can be difficult to manage. Children do best if they are diagnosed early and referred to a team of health care providers who can work on educational and behavioral strategies that fit the child’s needs.


Complications seen in the infant may include: 

  • Abnormal heart structure

  • Behavior problems

  • Infant death

  • Mental retardation

  • Problems in the structure of the head, eyes, nose, or mouth

  • Poor growth before birth

  • Slow growth and poor coordination after birth

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