Foetal Alcohol Syndrome (FAS)

How a mum-to-be’s drinking can have serious consequences on her baby’s growth and development.

The more you drink when you're pregnant, the greater the risk you are taking with your baby’s health. Miscarriage, stillbirth, premature birth and small birth weight are all associated with a mother’s drinking during pregnancy. Foetal exposure to alcohol is also the leading known cause of intellectual disability (1). All of these potential risks are why the government advises pregnant women and those trying to conceive to avoid alcohol altogether. 

View our Alcohol and pregnancy facts page for the full details of the government’s advice.

One condition you may not have heard of is called Foetal Alcohol Syndrome (FAS) and it affects the way a baby’s brain develops. First discovered by two doctors in the US in 1973, how serious the condition is depends on how much alcohol a mother drank during pregnancy. The World Health Organisation quotes a 2005 US study which estimated that one in every 1,000 children are born with FAS (2).

What is foetal alcohol syndrome?

Children with FAS have distinct facial features including: small and narrow eyes, a small head, a smooth area between the nose and the lips and a thin upper lip. They also show the following symptoms:

  • Hearing and ear problems
  • Mouth, teeth and facial problems
  • Weak immune system
  • Epilepsy
  • Liver damage
  • Kidney and heart defects
  • Cerebral palsy and other muscular problems
  • Height and weight issues
  • Hormonal disorders

How FAS develops during pregnancy

“When a pregnant woman drinks, the alcohol goes across the placenta to the foetus via the bloodstream,” says Dr Raja Mukherjee who works for Surrey and Borders Partnership NHS Foundation Trust. “The foetus’ liver isn’t fully formed, so it cannot metabolise the alcohol quickly enough.” At this stage, the baby has a high blood alcohol concentration. It therefore lacks oxygen and the nutrients needed for its brain and organs to grow properly. “White matter in the brain, which is responsible for speeding up the processing of information, is sensitive to alcohol,” says Dr Mukherjee. “So when a mother drinks, it affects the development of her baby’s white matter.”

Timing is another medical factor in the development of foetal alcohol syndrome. A baby’s facial features are formed during weeks six to nine of pregnancy. Professor Neil McIntosh, an Edinburgh-based neonatologist, says scientific evidence shows that mothers who drink during this three-week window are more likely to have babies with the facial deformities associated with FAS. Damage to the baby’s organs through drinking is most likely to happen in the first three months.

Want the facts on alcohol and pregnancy?

FASD signs and symptoms

Foetal Alcohol Spectrum Disorder (FASD) is the umbrella term used to describe the conditions that occur in people who have been diagnosed with some, but not all, of the symptoms of foetal alcohol syndrome. Like FAS, FASD is caused by a mother’s drinking during pregnancy, and it affects the way a baby develops physically and mentally. There are no accurate records of the incidence of FASD in Western countries, but experts estimate that it may be as high as one child in 100 is born with FASD (3) (4).

It is more difficult for a specialist to diagnose FASD than it is FAS. This is because children with FASD may not have facial deformities. It might not be until they start going to school and interacting with others that the following symptoms – which also affect children with foetal alcohol syndrome – show up:

  • Learning difficulties
  • Problems with language
  • Lack of appropriate social boundaries (such as over friendliness with strangers)
  • Poor short term memory
  • Inability to grasp instructions
  • Failure to learn from the consequences of their actions
  • Egocentricity
  • Mixing reality and fiction
  • Difficulty with group social interaction
  • Poor problem solving and planning
  • Hyperactivity and poor attention
  • Poor coordination.

Treatment for children

GPs can refer children with FAS and FASD to community paediatricians who are likely to investigate problems further with psychologists, psychiatrists, speech and language therapists and specialists for organ defects.

Dr Mukherjee runs a clinic for children and adults over six with FAS and FASD. He diagnoses FASD by excluding similar conditions such as Attention Deficit Hyperactivity Disorder (ADHD). “Then it’s about working with the child, parents and other professionals, such as teachers, to find a management strategy for the condition,” he says. “For example, parents can learn to repeat instructions for children and use simple language and teachers should allow them more time and provide extra supervision.”

Early diagnosis is key. Research shows that people who have FAS or FASD go on to experience “secondary disabilities” – those not present at birth – which could be prevented with appropriate support. These include mental health and alcohol and drug problems. “Early diagnosis allows the stability and management that children with FAS or FASD need to be invoked earlier,” says Professor McIntosh.

Advice for mums-to-be

We don’t know how much alcohol is safe to drink in pregnancy. It depends on various factors such as how fast a mum-to-be absorbs alcohol, her physical health, diet and what medication she is on. It’s why the government advises pregnant women and those trying to conceive to avoid alcohol altogether.

If you didn’t know you were pregnant and you have been drinking above the government’s lower risk guidelines, don’t panic. Talk to your GP or midwife about any concerns you may have. Just because you may have drunk does not mean you have necessarily done damage.

“If you drink a low amount when you are pregnant your baby has a low risk of developing FAS or FASD,” says Dr Mykherjee. “If you drink heavily you have a high risk. If you don’t drink, there’s no risk at all.”

Want more advice on drinking while pregnant?

Alcohol and conception

If you are trying to conceive, you should aim to reduce your alcohol consumption to a minimum, and ideally stop drinking altogether. If you are a regular drinker, try cutting down on alcohol gradually. Start off by reducing your drinking each day, and then try having a few alcohol free days a week before aiming to have only an occasional drink or preferably stop drinking altogether. Ask your partner to help you by cutting down drinking as well. If you are trying to conceive this is vital, as drinking impairs sperm count and heavy drinking can cause temporary impotence (5).

More information

The FASD Trust – The FASD Trust operates a helpline for parents and carers of children with FASD. Call 01608 811 599.

National Organisation on Foetal Alcohol Syndrome UK – Or call their helpline on 08700 333 700.

Health effects of alcohol

From the second you take your first sip, alcohol starts affecting your body and mind. Some of alcohol’s effects disappear overnight – while others can stay with you a lot longer, or indeed become permanent.

Health Effects Thumbnail

The effects of alcohol on your body

Use our interactive infographic to find out what effect alcohol has on your body.

Health Effects

When should you talk to your child about alcohol?

The age of your child’s first drink is crucial, so it’s important to talk to them before they have their first experience with alcohol.

Read our simple guide

Should your child be drinking alcohol?

When it comes to the risks of children drinking alcohol, they can be both short or long-term.

Understand the risks


Page updated: March 2015