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Fetal alcohol syndrome

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FAS is a pattern of disabilities that can develop in a baby as it grows in the womb (uterus) because the pregnant mother drinks too much alcohol.

Editor’s note

Dr Sarah Jarvis, 22nd March 2022

Please note that this information leaflet has been archived. That means it has not been updated since it was last reviewed and the information in it may not be up to date.

The National Institute for Health and Care Excellence (NICE) has published a new Quality Standard about fetal alcohol spectrum disorder since this article was updated. You can find out more about their recommendations from the further reading section at the end of this leaflet.

Fetal alcohol syndrome (FAS) is part of a group of conditions called fetal alcohol spectrum disorders (FASDs). These are a range of disabilities a child may be born with. They happen when his or her mother has been drinking alcohol while pregnant.

A child or person with FAS has differences in their face and head. They are smaller or shorter than average and have learning and behavioural difficulties.

Continue reading below

What is fetal alcohol syndrome?

FAS is a pattern of disabilities that can develop in a baby as it grows in the womb (uterus). It happens because the pregnant mother drinks too much alcohol.

FAS is one of a group of conditions. The whole group is called fetal alcohol spectrum disorders (FASDs). Other conditions within this range are:

  • Alcohol-related birth defects (ARBDs).

  • Partial fetal alcohol syndrome (pFAS).

  • Alcohol-related neurodevelopmental disorder (ARND).

People born with FAS have a set group of symptoms. These are different shapes to their faces, stunted growth and some mental difficulties. People with the other conditions in the spectrum may not have this exact match of problems. They have some of them, or other problems caused by alcohol before their birth.

How does fetal alcohol syndrome occur?

A baby in the womb (uterus) gets all its nourishment from its mother's bloodstream. Alcohol in the mother's blood can pass straight to the baby's blood. So if a pregnant mother drinks alcohol, it passes through the baby too. Alcohol is a toxic substance, so it can poison the developing fetus. In the nine months in the womb, the baby develops and forms. Poisons in the blood can damage the baby. The damage depends on which part is developing at that time. The brain is continually forming, so it can be damaged at any stage of pregnancy. In the first three months the organs are developing. So, this is the time when the heart, eyes and kidneys might be harmed. Later, when the fetus is growing fast, alcohol can slow this growth down.

Continue reading below

Who gets fetal alcohol syndrome?

FAS and FASDs only occur in babies born to mothers who drink alcohol during pregnancy. It is not known exactly how much alcohol is safe in pregnancy. Heavy drinking and binge drinking are more likely to cause damage to the baby.

Not every mother who drinks heavily in pregnancy has a baby with FAS. So there seem to be other factors that make it more likely to happen. These may include:

  • The genetic 'makeup' of the mother and baby. (This is the coding system inside each cell of our bodies. We inherit it from our parents. It makes us who we are and makes each of us different.)

  • How healthy the mother is.

  • How good the mother's diet is.

  • Whether the mother is stressed.

  • The mother's age.

  • Whether the mother smokes or not.

How common is fetal alcohol syndrome?

In the UK, it is not known exactly how common FAS is. This is because it is difficult to diagnose. Also, there is no system for reporting it. FAS is one of the most common reasons for children to have mental or behavioural problems, other than gene abnormalities.

There are big differences in how much people drink in different countries, and even between areas in the same country. Because of this, how often babies are born with FAS varies between places. In the USA it is estimated to occur in 2 to 15 of every 10,000 births. Other alcohol damage without the full syndrome of FAS happens much more commonly. It is thought between 2 and 5 of every one hundred schoolchildren may be affected in some way. In Italy FAS is thought to happen in up to 62 in every 1,000 births. In parts of South Africa it may be as often as 89 in every 1,000 births.

Continue reading below

What are the symptoms and signs of fetal alcohol syndrome?

FAS has three classic groups of abnormality.

Typical shape of the face

Differences include:

  • A small head.

  • The groove between the nose and lip is flattened.

  • A thin upper lip.

  • A flat bridge of the nose, which tends to be short and upturned.

  • Drooping eyelids (ptosis).

  • A 'railroad track' shape to the outer part of the ears.

  • Small eyes that are closer together.

  • Skin folds of the upper eyelids (epicanthic folds).

  • Clefts in the lip and/or palate can occur.

Stunted growth

Babies are small and grow up to be shorter than average.

Mental and behavioural difficulties

These happen because alcohol damages the brain as it forms. They include:

  • Lower-than-average IQ (not always).

  • Hyperactivity.

  • Difficulty with paying attention.

  • Memory problems.

  • Difficulty with seeing the consequences of one's own actions.

  • Poor judgement.

  • Impulsive behaviour and not being able to control impulses.

  • Poor problem-solving skills.

  • Difficulty understanding concepts such as time, money and maths.

  • Difficulty getting on with other people, immature behaviour, aggressive behaviour.

  • Speech and language delay.

  • Problems with sucking and feeding for the newborn baby (and sometimes symptoms of alcohol withdrawal).

There may also be some of the other problems from the whole range of FASD. These include:

  • Poor hearing or vision.

  • Abnormalities of the valves of the heart.

  • Kidney problems or genital abnormalities.

  • Bone and joint problems.

How is fetal alcohol syndrome diagnosed?

There is no test for FAS. It can only be diagnosed by spotting the typical features. Also by suspecting or knowing the mother may have drunk alcohol during pregnancy. Tests might be done to check there is no other reason for the abnormalities.

What is the treatment?

There is no particular treatment. Babies with FAS and FASDs will have the problems for the rest of their lives. However, if the condition is picked up early, they will experience the effects less. They can be helped and understood (see below).

What is the outlook?

There is no cure for FAS. Babies born with it will be affected throughout their lives. They are likely to do less well in school and get into trouble more. They tend to have problems making friends. When they grow up they are more likely to get into trouble with the police. They might have problems because of 'out of place' sexual behaviour. They might become addicted to alcohol or drugs. This is because they can't see the consequences of their actions. It is also because they can't control their impulses.

Getting the diagnosis of FAS right is good for the child. If it is known what is wrong with them, they can be helped. If the diagnosis is made early they will always get special help. They will have fewer problems if they are in a loving and understanding family. They can have extra help at school. Social workers can help children and adults with FAS. All the extra help and understanding will make it less likely that they will get into trouble.

If you have a child with FAS, support groups have information about how you can help them. With the right help they will do better in school. They will run into less trouble as adults.

How can fetal alcohol syndrome be prevented?

FAS is entirely preventable. If you are pregnant and do not drink alcohol, you will not have a baby with FAS. It is not known exactly how much alcohol it is safe to drink in pregnancy. So UK guidelines advise that it is safest not to drink any at all.

Further reading and references

Article history

The information on this page is written and peer reviewed by qualified clinicians.

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